| Topic: |
Science > Physics |
| User: |
"RichD" |
| Date: |
10 May 2007 06:04:42 PM |
| Object: |
efficiency of walking |
I was talking with someone about walking vs. bike riding,
and had to explain why walking is far less efficient: every
time your foot hits the pavement, bam, it's a dead stop;
large kinetic energy loss. It's remarkable how many
people don't get this. (another fun question: why does
a car get better highway, than city, fuel mileage?)
Now, the hard part: how inefficient is it? What is the
energy loss? It's a tough chestnut, on account of
ankle flexibility, which permits some continuous
motion of the body.
Suppose you were given this project, with adequate
funding: quantify it. i.e. how much energy is lost
on each foot step? How would you determine this?
What experimental apparatus and measurements
would you need? How accurate would be the results?
Bonus credit: discuss the relative efficiency of bicycle
vs. roller skates.
--
Rich
.
|
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| User: "Androcles" |
|
| Title: Re: efficiency of walking |
10 May 2007 06:53:00 PM |
|
|
"RichD" <r_delaney2001@yahoo.com> wrote in message =
news:1178838282.488631.276050@y80g2000hsf.googlegroups.com...
I was talking with someone about walking vs. bike riding,
and had to explain why walking is far less efficient: every
time your foot hits the pavement, bam, it's a dead stop;
large kinetic energy loss. It's remarkable how many
people don't get this.=20
Every time a wheel hits the pavement, bam, it's a dead stop.
Check it out:=20
http://mathworld.wolfram.com/Cycloid.html
It's not really remarkable how wrong you can be.
(another fun question: why does
a car get better highway, than city, fuel mileage?)
Time spent braking, idling and gear changing.=20
Braking is highly inefficient, KE is wasted as heat.
Predominantly wind resistance is overcome on the highway,
heating the air with friction, not the brakes.
Now, the hard part: how inefficient is it? What is the
energy loss? It's a tough chestnut, on account of
ankle flexibility, which permits some continuous
motion of the body.
Oh, we are back to walking again.=20
Bike riding is inefficient, when the pedal gets to the bottom
having been pushed *down*, bam, it's a dead stop.
Oddly enough pedals push the other foot up to the top=20
until bam, it's a dead stop.
Walking is inefficient if you swing your arms.
Riding a bike is little like climbing a hill, you lift yourself as=20
you step hard on the pedal, but having reached the top of=20
the hill you can glide down again.=20
=20
Suppose you were given this project, with adequate
funding: quantify it. i.e. how much energy is lost
on each foot step? How would you determine this?
I'd need to know food mileage. I'd starve you for a week,=20
feed you on one can of beans then put you on a treadmill=20
until you dropped, measuring weight change and calculating calories
from beans.=20
You can hold the side rails if you want to. Resting is allowed.
Then I'd repeat, starve you for a week, feed you one=20
more can of beans and put the bike on the treadmill.
I anticipate about the same food mileage. With adequate funding
I'd pay another a bonus if he got greater food mileage from walking=20
than you get from cycling to avoid any cheating. Since you would have
an axe to grind you'd get no bonus, so I'd give him an axe too to level=20
the playing field. =20
=20
What experimental apparatus and measurements
would you need? How accurate would be the results?
=20
Bonus credit: discuss the relative efficiency of bicycle
vs. roller skates.
Roller skates have smaller wheels which turn faster, creating
greater friction in the bearings.
Another week of starvation, another can of beans.
I anticipate less food mileage than walking.
.
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|
| User: "Fred Bloggs" |
|
| Title: Re: efficiency of walking |
12 May 2007 07:44:53 AM |
|
|
Androcles wrote:
Bike riding is inefficient, when the pedal gets to the bottom
having been pushed *down*, bam, it's a dead stop.
Oddly enough pedals push the other foot up to the top
until bam, it's a dead stop.
Walking is inefficient if you swing your arms.
Riding a bike is little like climbing a hill, you lift yourself as
you step hard on the pedal, but having reached the top of
the hill you can glide down again.
That's not how cycling is done, it is a rotary motion which means there
are no "bam" types of dead stops in the wheels or the legs. Duh, that's
why it's called a bi-*CYCLE*. As for the leg motion, the seat height is
adjusted so that the knee is fully extended when the pedal bottoms. The
leg is used to apply peak force on the pedal only through the last 20o
of pedal rotation at the bottom, the remaining portion of the cycle is
all momentum. The opposite leg pulls up and is definitely not pushed up
by the stroking leg. For most people, a constant pedal cadence of 90RPM
is optimal so as to assist the blood return to the heart, change gears
as necessary to maintain this cadence.
.
|
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|
|
| User: "jasen" |
|
| Title: Re: efficiency of walking |
11 May 2007 05:52:27 AM |
|
|
On 2007-05-10, Androcles <Engineer@hogwarts.physics.co.uk> wrote:
Oh, we are back to walking again.
Bike riding is inefficient, when the pedal gets to the bottom
having been pushed *down*, bam, it's a dead stop.
Oddly enough pedals push the other foot up to the top
until bam, it's a dead stop.
Walking is inefficient if you swing your arms.
Riding a bike is little like climbing a hill, you lift yourself as
you step hard on the pedal, but having reached the top of
the hill you can glide down again.
If it's like that you're in the wrong gear, change down.
expert cycllists work both pedals wityh both legs all the time.
(this needs special footeare and pedals or toe clips) This is called
spinning,
Bye.
Jasen
.
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|
| User: "Androcles" |
|
| Title: Re: efficiency of walking |
11 May 2007 11:08:20 AM |
|
|
"jasen" <jasen@free.net.nz> wrote in message =
news:f21htb$jgk$2@jasen.is-a-geek.org...
If it's like that you're in the wrong gear, change down.
=20
expert cycllists work both pedals wityh both legs all the time.
(this needs special footeare and pedals or toe clips) This is called
spinning,
Learn to spell, it's sort of like I might be able to know what you are =
babbling=20
about, kind of, if you know what I mean, "cycllists" "wityh" "footeare", =
if it's like,
.
|
|
|
| User: "John Larkin" |
|
| Title: Re: efficiency of walking |
11 May 2007 02:55:17 PM |
|
|
On Fri, 11 May 2007 16:08:20 GMT, "Androcles"
<Engineer@hogwarts.physics.co.uk> wrote:
"jasen" <jasen@free.net.nz> wrote in message news:f21htb$jgk$2@jasen.is-a-geek.org...
If it's like that you're in the wrong gear, change down.
expert cycllists work both pedals wityh both legs all the time.
(this needs special footeare and pedals or toe clips) This is called
spinning,
Learn to spell, it's sort of like I might be able to know what you are babbling
about, kind of, if you know what I mean, "cycllists" "wityh" "footeare", if it's like,
Your criticisms of his spelling might be slightly credible if you had
the physics right. You don't.
John
.
|
|
|
| User: "Androcles" |
|
| Title: Re: efficiency of walking |
11 May 2007 02:59:56 PM |
|
|
"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in =
message news:vei9435lu2kcg3h5bqkiifb5j23plu7mn0@4ax.com...
On Fri, 11 May 2007 16:08:20 GMT, "Androcles"
<Engineer@hogwarts.physics.co.uk> wrote:
=20
"jasen" <jasen@free.net.nz> wrote in message =
news:f21htb$jgk$2@jasen.is-a-geek.org...
If it's like that you're in the wrong gear, change down.
=20
expert cycllists work both pedals wityh both legs all the time.
(this needs special footeare and pedals or toe clips) This is called
spinning,
Learn to spell, it's sort of like I might be able to know what you are =
babbling=20
about, kind of, if you know what I mean, "cycllists" "wityh" =
"footeare", if it's like,
=20
Your criticisms of his spelling might be slightly credible if you had
the physics right. You don't.
=20
John
Hey fuckhead! Show where, ignoramus.
.
|
|
|
| User: "John Larkin" |
|
| Title: Re: efficiency of walking |
11 May 2007 03:41:08 PM |
|
|
On Fri, 11 May 2007 19:59:56 GMT, "Androcles"
<Engineer@hogwarts.physics.co.uk> wrote:
"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message news:vei9435lu2kcg3h5bqkiifb5j23plu7mn0@4ax.com...
On Fri, 11 May 2007 16:08:20 GMT, "Androcles"
<Engineer@hogwarts.physics.co.uk> wrote:
"jasen" <jasen@free.net.nz> wrote in message news:f21htb$jgk$2@jasen.is-a-geek.org...
If it's like that you're in the wrong gear, change down.
expert cycllists work both pedals wityh both legs all the time.
(this needs special footeare and pedals or toe clips) This is called
spinning,
Learn to spell, it's sort of like I might be able to know what you are babbling
about, kind of, if you know what I mean, "cycllists" "wityh" "footeare", if it's like,
Your criticisms of his spelling might be slightly credible if you had
the physics right. You don't.
John
Hey fuckhead! Show where, ignoramus.
Good grief, are you another incarnation of DampMatter?
John
.
|
|
|
| User: "Androcles" |
|
| Title: Re: efficiency of walking |
11 May 2007 04:38:00 PM |
|
|
"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in =
message news:h4l943phve5alr4ili92uh9459pitc75gi@4ax.com...
On Fri, 11 May 2007 19:59:56 GMT, "Androcles"
<Engineer@hogwarts.physics.co.uk> wrote:
=20
"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in =
message news:vei9435lu2kcg3h5bqkiifb5j23plu7mn0@4ax.com...
On Fri, 11 May 2007 16:08:20 GMT, "Androcles"
<Engineer@hogwarts.physics.co.uk> wrote:
=20
"jasen" <jasen@free.net.nz> wrote in message =
news:f21htb$jgk$2@jasen.is-a-geek.org...
If it's like that you're in the wrong gear, change down.
=20
expert cycllists work both pedals wityh both legs all the time.
(this needs special footeare and pedals or toe clips) This is =
called
spinning,
Learn to spell, it's sort of like I might be able to know what you =
are babbling=20
about, kind of, if you know what I mean, "cycllists" "wityh" =
"footeare", if it's like,
=20
Your criticisms of his spelling might be slightly credible if you =
had
the physics right. You don't.
=20
John
Hey fuckhead! Show where, ignoramus.
=20
Good grief, are you another incarnation of DampMatter?
Good grief, another troll with another new name making accusations he =
can't back up.
*****, *****.
*plonk*
.
|
|
|
| User: "Michael A. Terrell" |
|
| Title: Re: efficiency of walking |
11 May 2007 05:05:44 PM |
|
|
Androcles wrote:
"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message news:h4l943phve5alr4ili92uh9459pitc75gi@4ax.com...
On Fri, 11 May 2007 19:59:56 GMT, "Androcles"
<Engineer@hogwarts.physics.co.uk> wrote:
"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message news:vei9435lu2kcg3h5bqkiifb5j23plu7mn0@4ax.com...
On Fri, 11 May 2007 16:08:20 GMT, "Androcles"
<Engineer@hogwarts.physics.co.uk> wrote:
"jasen" <jasen@free.net.nz> wrote in message news:f21htb$jgk$2@jasen.is-a-geek.org...
If it's like that you're in the wrong gear, change down.
expert cycllists work both pedals wityh both legs all the time.
(this needs special footeare and pedals or toe clips) This is called
spinning,
Learn to spell, it's sort of like I might be able to know what you are babbling
about, kind of, if you know what I mean, "cycllists" "wityh" "footeare", if it's like,
Your criticisms of his spelling might be slightly credible if you had
the physics right. You don't.
John
Hey fuckhead! Show where, ignoramus.
Good grief, are you another incarnation of DampMatter?
Good grief, another troll with another new name making accusations he can't back up.
*****, *****.
*plonk*
You're an ignorant cross posting piece of foaming at the mouth
trash. According to the Google groups archive John has been around
sci.electronics.design since March first, 2004. He has made over 8000
posts with his real nname.
<http://groups.google.com/groups/profile?enc_user=Hl1L5yoAAAAOAq6aQiWIRoLH4xSKf1DEAGP0ZAA_j6Bl0ivhdzacHuRIK_oNlauL7omanA93z2Q&hl=en>
You, on the other hand:
Recent Activity:
Activity in All 87 Groups -- 2353 messages
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all made without a real name. What a lowlife coward.
--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.
Michael A. Terrell
Central Florida
.
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|
|
| User: "Androcles" |
|
| Title: Re: efficiency of walking |
11 May 2007 05:13:04 PM |
|
|
"Michael A. Terrell" <mike.terrell@earthlink.net> wrote in message =
news:4644E8C0.C064A060@earthlink.net...
Androcles wrote:
=20
"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in =
message news:h4l943phve5alr4ili92uh9459pitc75gi@4ax.com...
On Fri, 11 May 2007 19:59:56 GMT, "Androcles"
<Engineer@hogwarts.physics.co.uk> wrote:
"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in =
message news:vei9435lu2kcg3h5bqkiifb5j23plu7mn0@4ax.com...
On Fri, 11 May 2007 16:08:20 GMT, "Androcles"
<Engineer@hogwarts.physics.co.uk> wrote:
"jasen" <jasen@free.net.nz> wrote in message =
news:f21htb$jgk$2@jasen.is-a-geek.org...
If it's like that you're in the wrong gear, change down.
expert cycllists work both pedals wityh both legs all the time.
(this needs special footeare and pedals or toe clips) This is =
called
spinning,
Learn to spell, it's sort of like I might be able to know what =
you are babbling
about, kind of, if you know what I mean, "cycllists" "wityh" =
"footeare", if it's like,
Your criticisms of his spelling might be slightly credible if you =
had
the physics right. You don't.
John
Hey fuckhead! Show where, ignoramus.
Good grief, are you another incarnation of DampMatter?
=20
Good grief, another troll with another new name making accusations he =
can't back up.
*****, *****.
*plonk*
=20
=20
You're an ignorant=20
*****, *****.
*plonk*
.
|
|
|
| User: "Michael A. Terrell" |
|
| Title: Re: efficiency of walking |
11 May 2007 05:25:27 PM |
|
|
Androcles wrote:
*****, *****.
*plonk*
The truth really hurts doesn't it, Queenie? BTW, did you ever find a
date on alt.personals.transgendered, or are you so ugly in drag that the
other queens won't talk to you? Its really sad that nothing on earth
wants anything to do with your queer *****. You really should learn to
cover your tracks in the Goggle Gropers Archives, Queenie.
--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.
Michael A. Terrell
Central Florida
.
|
|
|
|
|
| User: "John Larkin" |
|
| Title: Re: efficiency of walking |
11 May 2007 06:00:13 PM |
|
|
On Fri, 11 May 2007 22:05:44 GMT, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:
Androcles wrote:
"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message news:h4l943phve5alr4ili92uh9459pitc75gi@4ax.com...
On Fri, 11 May 2007 19:59:56 GMT, "Androcles"
<Engineer@hogwarts.physics.co.uk> wrote:
"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message news:vei9435lu2kcg3h5bqkiifb5j23plu7mn0@4ax.com...
On Fri, 11 May 2007 16:08:20 GMT, "Androcles"
<Engineer@hogwarts.physics.co.uk> wrote:
"jasen" <jasen@free.net.nz> wrote in message news:f21htb$jgk$2@jasen.is-a-geek.org...
If it's like that you're in the wrong gear, change down.
expert cycllists work both pedals wityh both legs all the time.
(this needs special footeare and pedals or toe clips) This is called
spinning,
Learn to spell, it's sort of like I might be able to know what you are babbling
about, kind of, if you know what I mean, "cycllists" "wityh" "footeare", if it's like,
Your criticisms of his spelling might be slightly credible if you had
the physics right. You don't.
John
Hey fuckhead! Show where, ignoramus.
Good grief, are you another incarnation of DampMatter?
Good grief, another troll with another new name making accusations he can't back up.
*****, *****.
*plonk*
You're an ignorant cross posting piece of foaming at the mouth
trash. According to the Google groups archive John has been around
sci.electronics.design since March first, 2004. He has made over 8000
posts with his real nname.
<http://groups.google.com/groups/profile?enc_user=Hl1L5yoAAAAOAq6aQiWIRoLH4xSKf1DEAGP0ZAA_j6Bl0ivhdzacHuRIK_oNlauL7omanA93z2Q&hl=en>
You, on the other hand:
Recent Activity:
Activity in All 87 Groups -- 2353 messages
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all made without a real name. What a lowlife coward.
Fat transgendered atheist astrologers? Gosh, he sure does get around.
But clearly not on bicycles.
I thought maybe he was yet another nym of MassiveProng. He's every bit
as wrong and almost as aggressive.
John
.
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|
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| User: "Michael A. Terrell" |
|
| Title: Re: efficiency of walking |
11 May 2007 06:43:13 PM |
|
|
John Larkin wrote:
On Fri, 11 May 2007 22:05:44 GMT, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:
Androcles wrote:
"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message news:h4l943phve5alr4ili92uh9459pitc75gi@4ax.com...
On Fri, 11 May 2007 19:59:56 GMT, "Androcles"
<Engineer@hogwarts.physics.co.uk> wrote:
"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message news:vei9435lu2kcg3h5bqkiifb5j23plu7mn0@4ax.com...
On Fri, 11 May 2007 16:08:20 GMT, "Androcles"
<Engineer@hogwarts.physics.co.uk> wrote:
"jasen" <jasen@free.net.nz> wrote in message news:f21htb$jgk$2@jasen.is-a-geek.org...
If it's like that you're in the wrong gear, change down.
expert cycllists work both pedals wityh both legs all the time.
(this needs special footeare and pedals or toe clips) This is called
spinning,
Learn to spell, it's sort of like I might be able to know what you are babbling
about, kind of, if you know what I mean, "cycllists" "wityh" "footeare", if it's like,
Your criticisms of his spelling might be slightly credible if you had
the physics right. You don't.
John
Hey fuckhead! Show where, ignoramus.
Good grief, are you another incarnation of DampMatter?
Good grief, another troll with another new name making accusations he can't back up.
*****, *****.
*plonk*
You're an ignorant cross posting piece of foaming at the mouth
trash. According to the Google groups archive John has been around
sci.electronics.design since March first, 2004. He has made over 8000
posts with his real nname.
<http://groups.google.com/groups/profile?enc_user=Hl1L5yoAAAAOAq6aQiWIRoLH4xSKf1DEAGP0ZAA_j6Bl0ivhdzacHuRIK_oNlauL7omanA93z2Q&hl=en>
You, on the other hand:
Recent Activity:
Activity in All 87 Groups -- 2353 messages
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all made without a real name. What a lowlife coward.
Fat transgendered atheist astrologers? Gosh, he sure does get around.
But clearly not on bicycles.
I thought maybe he was yet another nym of MassiveProng. He's every bit
as wrong and almost as aggressive.
John
He is just another "Dead from the neck up" idiot.
--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.
Michael A. Terrell
Central Florida
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| User: "John Larkin" |
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| Title: Re: efficiency of walking |
11 May 2007 10:34:46 AM |
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On Thu, 10 May 2007 23:53:00 GMT, "Androcles"
<Engineer@hogwarts.physics.co.uk> wrote:
"RichD" <r_delaney2001@yahoo.com> wrote in message news:1178838282.488631.276050@y80g2000hsf.googlegroups.com...
I was talking with someone about walking vs. bike riding,
and had to explain why walking is far less efficient: every
time your foot hits the pavement, bam, it's a dead stop;
large kinetic energy loss. It's remarkable how many
people don't get this.
Every time a wheel hits the pavement, bam, it's a dead stop.
Check it out:
http://mathworld.wolfram.com/Cycloid.html
That's an optical ilusion. If it went BAM, you'd hear it. But you
don't. Seen from the viewpoint of the axle, which after all is where
the power is applied, the entire wheel rotates smoothly and
continuously. And the pavement flows by smoothly. Nothing goes BAM.
It's not really remarkable how wrong you can be.
Several sources, easy to find with google, cite bicycling as 3 or 4
times more efficient than walking. A common-dense mental experiment
will show that bicycling is much more efficient.
John
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| User: "Rich Grise" |
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| Title: Re: efficiency of walking |
11 May 2007 02:32:02 PM |
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On Fri, 11 May 2007 08:34:46 -0700, John Larkin wrote:
On Thu, 10 May 2007 23:53:00 GMT, "Androcles"
"RichD" <r_delaney2001@yahoo.com> wrote in message news:1178838282.488631.276050@y80g2000hsf.googlegroups.com...
I was talking with someone about walking vs. bike riding,
and had to explain why walking is far less efficient: every
time your foot hits the pavement, bam, it's a dead stop;
large kinetic energy loss. It's remarkable how many
people don't get this.
Every time a wheel hits the pavement, bam, it's a dead stop.
Check it out:
http://mathworld.wolfram.com/Cycloid.html
That's an optical ilusion. If it went BAM, you'd hear it. But you
don't. Seen from the viewpoint of the axle, which after all is where
the power is applied, the entire wheel rotates smoothly and
continuously. And the pavement flows by smoothly. Nothing goes BAM.
It's a sort of continuous soft slap, which comes out as sort of a
hiss.
And a dead stop is nothing! The flanges on train wheels actually go
backwards! =:-O
;-)
Cheers!
Rich
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| User: "krw" |
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| Title: Re: efficiency of walking |
10 May 2007 06:26:25 PM |
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In article <1178838282.488631.276050@y80g2000hsf.googlegroups.com>,
r_delaney2001@yahoo.com says...
I was talking with someone about walking vs. bike riding,
and had to explain why walking is far less efficient: every
time your foot hits the pavement, bam, it's a dead stop;
large kinetic energy loss. It's remarkable how many
people don't get this. (another fun question: why does
a car get better highway, than city, fuel mileage?)
I think you'll find that bipedal locomotion is remarkably efficient,
though muscles aren't all that efficient. There is a lot of
information on this in robotics papers, if you care to chase it (try
doing a search on "efficiency + human + walking (or locomotion)".
Now, the hard part: how inefficient is it? What is the
energy loss? It's a tough chestnut, on account of
ankle flexibility, which permits some continuous
motion of the body.
Some? The body doesn't come to a stop when walking.
Suppose you were given this project, with adequate
funding: quantify it. i.e. how much energy is lost
on each foot step? How would you determine this?
What experimental apparatus and measurements
would you need? How accurate would be the results?
Try: http://jap.physiology.org/cgi/content/full/95/1/172
I only quickly perused it, but there seems to be a lot of methodology
in there.
Bonus credit: discuss the relative efficiency of bicycle
vs. roller skates.
--
Keith
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| User: "qrk" |
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| Title: Re: efficiency of walking |
11 May 2007 01:05:33 PM |
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On 10 May 2007 16:04:42 -0700, RichD <r_delaney2001@yahoo.com> wrote:
I was talking with someone about walking vs. bike riding,
and had to explain why walking is far less efficient: every
time your foot hits the pavement, bam, it's a dead stop;
large kinetic energy loss. It's remarkable how many
people don't get this. (another fun question: why does
a car get better highway, than city, fuel mileage?)
Now, the hard part: how inefficient is it? What is the
energy loss? It's a tough chestnut, on account of
ankle flexibility, which permits some continuous
motion of the body.
Suppose you were given this project, with adequate
funding: quantify it. i.e. how much energy is lost
on each foot step? How would you determine this?
What experimental apparatus and measurements
would you need? How accurate would be the results?
Bonus credit: discuss the relative efficiency of bicycle
vs. roller skates.
From "Bicycling Science", Whitt & Wilson, pg. 5.
Propulsioin pwr, hp per long ton at 3 mph, air resistance neglected.
Vehicle Pwr
==================== ======
Rail car 0.04
Bicycle 0.1
Car 0.3
Horse 0.6
Man 1.0
Leaping rabbits 3.2
Crawling caterpillar 16
Snake sliding uphill 20+
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| User: "John Larkin" |
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| Title: Re: efficiency of walking |
11 May 2007 08:33:50 PM |
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On Fri, 11 May 2007 18:05:33 GMT, qrk <SpamTrap@spam.net> wrote:
On 10 May 2007 16:04:42 -0700, RichD <r_delaney2001@yahoo.com> wrote:
I was talking with someone about walking vs. bike riding,
and had to explain why walking is far less efficient: every
time your foot hits the pavement, bam, it's a dead stop;
large kinetic energy loss. It's remarkable how many
people don't get this. (another fun question: why does
a car get better highway, than city, fuel mileage?)
Now, the hard part: how inefficient is it? What is the
energy loss? It's a tough chestnut, on account of
ankle flexibility, which permits some continuous
motion of the body.
Suppose you were given this project, with adequate
funding: quantify it. i.e. how much energy is lost
on each foot step? How would you determine this?
What experimental apparatus and measurements
would you need? How accurate would be the results?
Bonus credit: discuss the relative efficiency of bicycle
vs. roller skates.
From "Bicycling Science", Whitt & Wilson, pg. 5.
Propulsioin pwr, hp per long ton at 3 mph, air resistance neglected.
Vehicle Pwr
==================== ======
Rail car 0.04
Bicycle 0.1
Car 0.3
Horse 0.6
Man 1.0
Leaping rabbits 3.2
Crawling caterpillar 16
Snake sliding uphill 20+
That's 10:1 for the bicycle, except that people usually pedal fast
enough - not 3 mph! - that air resistance becomes a substantial
fraction of the losses.
And how many caterpillars can make 3 mph?
John
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| User: "John Larkin" |
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| Title: Re: efficiency of walking |
11 May 2007 11:01:38 AM |
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On 10 May 2007 16:04:42 -0700, RichD <r_delaney2001@yahoo.com> wrote:
I was talking with someone about walking vs. bike riding,
and had to explain why walking is far less efficient: every
time your foot hits the pavement, bam, it's a dead stop;
large kinetic energy loss. It's remarkable how many
people don't get this. (another fun question: why does
a car get better highway, than city, fuel mileage?)
Now, the hard part: how inefficient is it? What is the
energy loss? It's a tough chestnut, on account of
ankle flexibility, which permits some continuous
motion of the body.
Suppose you were given this project, with adequate
funding: quantify it. i.e. how much energy is lost
on each foot step? How would you determine this?
What experimental apparatus and measurements
would you need? How accurate would be the results?
Just imagine walking at some nice rate, and how much your breathing
and heart rate would be elevated. Now imagine pedalling a bike at that
same level of exertion. Pretty obviously, you'd be going a lot faster
on the bike.
You could quantify this by equalizing heart or respiratory rates
between walking and biking (you need only a wristwatch and some
patience), or more precisely by measuring CO2 production.
John
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| User: "jasen" |
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| Title: Re: efficiency of walking |
11 May 2007 05:47:19 AM |
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On 2007-05-10, RichD <r_delaney2001@yahoo.com> wrote:
Suppose you were given this project, with adequate
funding: quantify it. i.e. how much energy is lost
on each foot step?
not much, I expect more is lost repeatedly lifting
and lowering the body.
air-filled soles annt other footware technology
can help on many levels.
How would you determine this?
What experimental apparatus and measurements
would you need? How accurate would be the results?
exhaled CO2. treadmills, and other exercise machinery.
Bonus credit: discuss the relative efficiency of bicycle
vs. roller skates.
depends on skating style.
if the trip involves a very steep hill the skates may come out ahead.
Bye.
Jasen
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| User: "J.A. Legris" |
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| Title: Re: efficiency of walking |
11 May 2007 09:11:13 AM |
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On May 10, 7:04 pm, RichD <r_delaney2...@yahoo.com> wrote:
I was talking with someone about walking vs. bike riding,
and had to explain why walking is far less efficient: every
time your foot hits the pavement, bam, it's a dead stop;
large kinetic energy loss. It's remarkable how many
people don't get this. (another fun question: why does
a car get better highway, than city, fuel mileage?)
Now, the hard part: how inefficient is it? What is the
energy loss? It's a tough chestnut, on account of
ankle flexibility, which permits some continuous
motion of the body.
Suppose you were given this project, with adequate
funding: quantify it. i.e. how much energy is lost
on each foot step? How would you determine this?
What experimental apparatus and measurements
would you need? How accurate would be the results?
Bonus credit: discuss the relative efficiency of bicycle
vs. roller skates.
--
Rich
I believe cycling can be much more efficient than walking, but the
collisions with the ground are probably rather elastic, with energy
being stored and released by the springy tendons of the (youthful)
legs. That being said, tendons are not perfect springs and muscles
have to be stretched, so there are significant losses occurring with
every step. Meahwhile a chubby cyclist coasts by. I read somewhere
that cycling uses just 1/5 of the energy of walking!
--
Joe
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| User: "OG" |
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| Title: Re: efficiency of walking |
14 May 2007 04:41:32 PM |
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"J.A. Legris" <jalegris@sympatico.ca> wrote in message
news:1178892673.264330.232900@u30g2000hsc.googlegroups.com...
On May 10, 7:04 pm, RichD <r_delaney2...@yahoo.com> wrote:
I was talking with someone about walking vs. bike riding,
and had to explain why walking is far less efficient: every
time your foot hits the pavement, bam, it's a dead stop;
large kinetic energy loss. It's remarkable how many
people don't get this. (another fun question: why does
a car get better highway, than city, fuel mileage?)
Now, the hard part: how inefficient is it? What is the
energy loss? It's a tough chestnut, on account of
ankle flexibility, which permits some continuous
motion of the body.
Suppose you were given this project, with adequate
funding: quantify it. i.e. how much energy is lost
on each foot step? How would you determine this?
What experimental apparatus and measurements
would you need? How accurate would be the results?
Bonus credit: discuss the relative efficiency of bicycle
vs. roller skates.
--
Rich
I believe cycling can be much more efficient than walking, but the
collisions with the ground are probably rather elastic, with energy
being stored and released by the springy tendons of the (youthful)
legs. That being said, tendons are not perfect springs and muscles
have to be stretched, so there are significant losses occurring with
every step. Meahwhile a chubby cyclist coasts by. I read somewhere
that cycling uses just 1/5 of the energy of walking!
The talk about 'bam your foot stops' is not really helpful because the foot
has only a small mass, hence little power is needed to get it moving; most
of the mass of the body moves at a fairly constant speed.
I had a look at some websites that claim to give energy stats for various
exercises.
If the resting body has a base energy expenditure (power) of 1, walking at
pace has a power of 3, whereas cycling would be about 1.5.
I've heard a quote that the most energy efficient means of sustained
transport* in the whole of the animal kingdom is a thin person on a bike.
*excluding drifting etc.
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| User: "krw" |
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| Title: Re: efficiency of walking |
14 May 2007 07:31:36 PM |
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In article <R-SdnaQZb5AJStXbnZ2dnUVZ8vednZ2d@pipex.net>,
owen@gwynnefamily.org.uk says...
"J.A. Legris" <jalegris@sympatico.ca> wrote in message
news:1178892673.264330.232900@u30g2000hsc.googlegroups.com...
On May 10, 7:04 pm, RichD <r_delaney2...@yahoo.com> wrote:
I was talking with someone about walking vs. bike riding,
and had to explain why walking is far less efficient: every
time your foot hits the pavement, bam, it's a dead stop;
large kinetic energy loss. It's remarkable how many
people don't get this. (another fun question: why does
a car get better highway, than city, fuel mileage?)
Now, the hard part: how inefficient is it? What is the
energy loss? It's a tough chestnut, on account of
ankle flexibility, which permits some continuous
motion of the body.
Suppose you were given this project, with adequate
funding: quantify it. i.e. how much energy is lost
on each foot step? How would you determine this?
What experimental apparatus and measurements
would you need? How accurate would be the results?
Bonus credit: discuss the relative efficiency of bicycle
vs. roller skates.
--
Rich
I believe cycling can be much more efficient than walking, but the
collisions with the ground are probably rather elastic, with energy
being stored and released by the springy tendons of the (youthful)
legs. That being said, tendons are not perfect springs and muscles
have to be stretched, so there are significant losses occurring with
every step. Meahwhile a chubby cyclist coasts by. I read somewhere
that cycling uses just 1/5 of the energy of walking!
The talk about 'bam your foot stops' is not really helpful because the foot
has only a small mass, hence little power is needed to get it moving; most
of the mass of the body moves at a fairly constant speed.
I had a look at some websites that claim to give energy stats for various
exercises.
If the resting body has a base energy expenditure (power) of 1, walking at
pace has a power of 3, whereas cycling would be about 1.5.
I've heard a quote that the most energy efficient means of sustained
transport* in the whole of the animal kingdom is a thin person on a bike.
*excluding drifting etc.
I've heard that too. Thsy also say that man is the fastest animal at
long distances. Many believe that early man ran his prey to death.
Bipedal locomotion is quite efficient, compared to the rest of the
animals. Significant energy is stored and released in the tendons
during the stride.
--
Keith
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| User: "Rich Grise" |
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| Title: Re: efficiency of walking |
14 May 2007 08:25:13 PM |
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On Mon, 14 May 2007 22:41:32 +0100, OG wrote:
"J.A. Legris" <jalegris@sympatico.ca> wrote in message
news:1178892673.264330.232900@u30g2000hsc.googlegroups.com...
On May 10, 7:04 pm, RichD <r_delaney2...@yahoo.com> wrote:
I was talking with someone about walking vs. bike riding,
and had to explain why walking is far less efficient: every
time your foot hits the pavement, bam, it's a dead stop;
large kinetic energy loss. It's remarkable how many
people don't get this. (another fun question: why does
a car get better highway, than city, fuel mileage?)
Now, the hard part: how inefficient is it? What is the
energy loss? It's a tough chestnut, on account of
ankle flexibility, which permits some continuous
motion of the body.
Suppose you were given this project, with adequate
funding: quantify it. i.e. how much energy is lost
on each foot step? How would you determine this?
What experimental apparatus and measurements
would you need? How accurate would be the results?
Bonus credit: discuss the relative efficiency of bicycle
vs. roller skates.
--
Rich
I believe cycling can be much more efficient than walking, but the
collisions with the ground are probably rather elastic, with energy
being stored and released by the springy tendons of the (youthful)
legs. That being said, tendons are not perfect springs and muscles
have to be stretched, so there are significant losses occurring with
every step. Meahwhile a chubby cyclist coasts by. I read somewhere
that cycling uses just 1/5 of the energy of walking!
The talk about 'bam your foot stops' is not really helpful because the foot
has only a small mass, hence little power is needed to get it moving; most
of the mass of the body moves at a fairly constant speed.
I had a look at some websites that claim to give energy stats for various
exercises.
If the resting body has a base energy expenditure (power) of 1, walking at
pace has a power of 3, whereas cycling would be about 1.5.
I've heard a quote that the most energy efficient means of sustained
transport* in the whole of the animal kingdom is a thin person on a bike.
*excluding drifting etc.
I've seen a graph, and it's something like this:
| *
| *
| * * human on bicycle
| *
| *
| * <- various means of transport
| * (animals, whales, trains, etc.)
| *
| *
0------------------------------------
Where the axes are like "mass" vs "energy efficiency" or something like
that.
I have no idea how to look it up, or even if there's one on the internet.
Thanks,
Rich
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| User: "Igor" |
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| Title: Re: efficiency of walking |
11 May 2007 12:34:34 PM |
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On May 10, 7:04 pm, RichD <r_delaney2...@yahoo.com> wrote:
I was talking with someone about walking vs. bike riding,
and had to explain why walking is far less efficient: every
time your foot hits the pavement, bam, it's a dead stop;
large kinetic energy loss. It's remarkable how many
people don't get this. (another fun question: why does
a car get better highway, than city, fuel mileage?)
Your center of mass never comes to a dead stop when your foot hits the
pavement, so I think your argument is bogus. And when one foot stops,
the other one is usually already in motion, so you might want to
rethink all of this.
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| User: "Rich Grise" |
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| Title: Re: efficiency of walking |
11 May 2007 02:39:52 PM |
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On Fri, 11 May 2007 10:34:34 -0700, Igor wrote:
On May 10, 7:04 pm, RichD <r_delaney2...@yahoo.com> wrote:
I was talking with someone about walking vs. bike riding,
and had to explain why walking is far less efficient: every
time your foot hits the pavement, bam, it's a dead stop;
large kinetic energy loss. It's remarkable how many
people don't get this. (another fun question: why does
a car get better highway, than city, fuel mileage?)
Your center of mass never comes to a dead stop when your foot hits the
pavement, so I think your argument is bogus. And when one foot stops,
the other one is usually already in motion, so you might want to
rethink all of this.
The inefficiency comes in from the fact that while your center of mass
continues forward, you're applying a force to your foot which tends
to propel you forward, PLUS you're supporting the weight of your body,
and flexing/relaxing your muscles to keep yourself vertical and absorb
the bounce.
It's easy to notice the difference when walking uphill. When walking
downhill, you can't coast, so you don't get all that potential energy
back, and have to expend energy to "put on the brakes", as it were.
Cheers!
Rich
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| User: "Rich Grise" |
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| Title: Re: efficiency of walking |
10 May 2007 06:52:36 PM |
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On Thu, 10 May 2007 16:04:42 -0700, RichD wrote:
I was talking with someone about walking vs. bike riding,
and had to explain why walking is far less efficient: every
time your foot hits the pavement, bam, it's a dead stop;
large kinetic energy loss. It's remarkable how many
people don't get this. (another fun question: why does
a car get better highway, than city, fuel mileage?)
Now, the hard part: how inefficient is it? What is the
energy loss? It's a tough chestnut, on account of
ankle flexibility, which permits some continuous
motion of the body.
Suppose you were given this project, with adequate
funding: quantify it. i.e. how much energy is lost
on each foot step? How would you determine this?
What experimental apparatus and measurements
would you need? How accurate would be the results?
Bonus credit: discuss the relative efficiency of bicycle
vs. roller skates.
Put the guy on one of those medical treadmill things and measure
his O2 intake/CO2 output. From that, and something like "how much
energy is released when one ATP molecule gets metabolized", you
should be able to figure out joules (or watt-hours, or calories,
or whatever) per pound-mile.
I once read that a human on a bicycle is the most effecient form
of transportation, in terms of, say, watt-hours per pound-mile,
that there is.
http://www.exploratorium.edu/cycling/images/efficeincy.gif
Good Luck!
Rich
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| User: "Frank Miles" |
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| Title: Re: efficiency of walking |
11 May 2007 11:05:10 AM |
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In article <pan.2007.05.11.00.53.19.444477@example.net>,
Rich Grise <rich@example.net> wrote:
On Thu, 10 May 2007 16:04:42 -0700, RichD wrote:
I was talking with someone about walking vs. bike riding,
and had to explain why walking is far less efficient: every
time your foot hits the pavement, bam, it's a dead stop;
large kinetic energy loss. It's remarkable how many
people don't get this. (another fun question: why does
a car get better highway, than city, fuel mileage?)
Now, the hard part: how inefficient is it? What is the
energy loss? It's a tough chestnut, on account of
ankle flexibility, which permits some continuous
motion of the body.
You can get much better information by reading "Bicycling Science",
now in its third edition.
Suppose you were given this project, with adequate
funding: quantify it. i.e. how much energy is lost
on each foot step? How would you determine this?
What experimental apparatus and measurements
would you need? How accurate would be the results?
Bonus credit: discuss the relative efficiency of bicycle
vs. roller skates.
Put the guy on one of those medical treadmill things and measure
his O2 intake/CO2 output. From that, and something like "how much
energy is released when one ATP molecule gets metabolized", you
should be able to figure out joules (or watt-hours, or calories,
or whatever) per pound-mile.
I once read that a human on a bicycle is the most effecient form
of transportation, in terms of, say, watt-hours per pound-mile,
that there is.
http://www.exploratorium.edu/cycling/images/efficeincy.gif
Try rail (think steel wheels on steel rails, very little rolling
resistance; plus "drafting" of adjacent cars.
-f
--
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| User: "Jeff L" |
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| Title: Re: efficiency of walking |
12 May 2007 12:15:52 PM |
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"Frank Miles" <fpm@u.washington.edu> wrote in message
news:f2247m$tsi$1@gnus01.u.washington.edu...
In article <pan.2007.05.11.00.53.19.444477@example.net>,
Rich Grise <rich@example.net> wrote:
On Thu, 10 May 2007 16:04:42 -0700, RichD wrote:
I was talking with someone about walking vs. bike riding,
and had to explain why walking is far less efficient: every
time your foot hits the pavement, bam, it's a dead stop;
large kinetic energy loss. It's remarkable how many
people don't get this. (another fun question: why does
a car get better highway, than city, fuel mileage?)
Now, the hard part: how inefficient is it? What is the
energy loss? It's a tough chestnut, on account of
ankle flexibility, which permits some continuous
motion of the body.
You can get much better information by reading "Bicycling Science",
now in its third edition.
Suppose you were given this project, with adequate
funding: quantify it. i.e. how much energy is lost
on each foot step? How would you determine this?
What experimental apparatus and measurements
would you need? How accurate would be the results?
Bonus credit: discuss the relative efficiency of bicycle
vs. roller skates.
Put the guy on one of those medical treadmill things and measure
his O2 intake/CO2 output. From that, and something like "how much
energy is released when one ATP molecule gets metabolized", you
should be able to figure out joules (or watt-hours, or calories,
or whatever) per pound-mile.
I once read that a human on a bicycle is the most effecient form
of transportation, in terms of, say, watt-hours per pound-mile,
that there is.
http://www.exploratorium.edu/cycling/images/efficeincy.gif
Try rail (think steel wheels on steel rails, very little rolling
resistance; plus "drafting" of adjacent cars.
Then look at Mag lev trains then - almost no "rolling" resistance, just the
air resistance, which unfortunately carries a squared term with respect to
speed.
-f
--
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| User: "Rich Grise" |
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| Title: Re: efficiency of walking |
11 May 2007 02:28:53 PM |
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On Fri, 11 May 2007 16:05:10 +0000, Frank Miles wrote:
Rich Grise <rich@example.net> wrote:
....
http://www.exploratorium.edu/cycling/images/efficeincy.gif
Try rail (think steel wheels on steel rails, very little rolling
resistance; plus "drafting" of adjacent cars.
Did you even look at the chart? Train and riders at 30 MPH is about
100 Kcal/Kg/person, where a bike is about 10 or 20, albeit at 10
or 15 MPH.
Apparently, speed costs. ;-)
Thanks,
Rich
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| User: "Stanislaw Flatto" |
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| Title: Re: efficiency of walking |
10 May 2007 06:53:47 PM |
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RichD wrote:
I was talking with someone about walking vs. bike riding,
and had to explain why walking is far less efficient: every
time your foot hits the pavement, bam, it's a dead stop;
large kinetic energy loss. It's remarkable how many
people don't get this. (another fun question: why does
a car get better highway, than city, fuel mileage?)
Now, the hard part: how inefficient is it? What is the
energy loss? It's a tough chestnut, on account of
ankle flexibility, which permits some continuous
motion of the body.
Suppose you were given this project, with adequate
funding: quantify it. i.e. how much energy is lost
on each foot step? How would you determine this?
What experimental apparatus and measurements
would you need? How accurate would be the results?
Bonus credit: discuss the relative efficiency of bicycle
vs. roller skates.
--
Rich
Try to throw to Googgle the name of Shaul Ladany, he IS a mechanical
engineer and a walker. It maybe more in line to your qwerry.
Why to look for it in electronics?
HTH
Stanislaw.
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| User: "Dirk Bruere at NeoPax" |
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| Title: Re: efficiency of walking |
15 May 2007 05:13:46 PM |
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RichD wrote:
I was talking with someone about walking vs. bike riding,
and had to explain why walking is far less efficient: every
time your foot hits the pavement, bam, it's a dead stop;
large kinetic energy loss. It's remarkable how many
people don't get this. (another fun question: why does
a car get better highway, than city, fuel mileage?)
Now, the hard part: how inefficient is it? What is the
energy loss? It's a tough chestnut, on account of
ankle flexibility, which permits some continuous
motion of the body.
Suppose you were given this project, with adequate
funding: quantify it. i.e. how much energy is lost
on each foot step? How would you determine this?
What experimental apparatus and measurements
would you need? How accurate would be the results?
Bonus credit: discuss the relative efficiency of bicycle
vs. roller skates.
--
Rich
You could try these
http://www.springwalker.com/
http://www.powerskip.de/mainpage.html
--
Dirk
http://www.onetribe.me.uk - The UK's only occult talk show
Presented by Dirk Bruere and Marc Power
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| User: "Andy Resnick" |
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| Title: Re: efficiency of walking |
11 May 2007 08:35:29 AM |
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RichD wrote:
I was talking with someone about walking vs. bike riding,
and had to explain why walking is far less efficient: every
time your foot hits the pavement, bam, it's a dead stop;
large kinetic energy loss. It's remarkable how many
people don't get this. (another fun question: why does
a car get better highway, than city, fuel mileage?)
Now, the hard part: how inefficient is it? What is the
energy loss? It's a tough chestnut, on account of
ankle flexibility, which permits some continuous
motion of the body.
Suppose you were given this project, with adequate
funding: quantify it. i.e. how much energy is lost
on each foot step? How would you determine this?
What experimental apparatus and measurements
would you need? How accurate would be the results?
A rough calculation is not difficult: measurements have been made of 'x
calories per hour of [] activity'. You may choose to peform better
measurements, but let's start with walking at 100 kcal/hour for a 150
pound person walking at 5 mph. From this you can calculate the power
expended, and compare that against other processes. Before you make the
problem intractable by anatomical considerations, you may be better off
discussing the role of terrain.
Bonus credit: discuss the relative efficiency of bicycle
vs. roller skates.
--
Rich
--
Andrew Resnick, Ph.D.
Department of Physiology and Biophysics
Case Western Reserve University
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