| Topic: |
Science > Physics |
| User: |
"kjm" |
| Date: |
08 Dec 2003 10:40:28 PM |
| Object: |
f=ma, basic physics and self-defense |
my karate instructor asked the class if they understood the equation f=ma.
he led me along to say with him that if you swing (or send out) your fist
faster (thus increasing acceleration of the fist etc) the force applied is,
by this relationship, also greater. I didn't mention that I only have
understood f=ma to mean that a mass accelerating has a certain force acting
upon it. can this equation alone support the idea that the faster the punch
the more forceful the blow?
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| User: "Krzysztof Olczyk olczykdotkrzysztofatxldotwpdotpl" |
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| Title: Re: f=ma, basic physics and self-defense - only an approximation |
09 Dec 2003 08:21:49 AM |
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"kjm" <newsbox@NOSPAMbwknight.net> wrote in message
news:0ncBb.6971$7p2.6532@newsread2.news.atl.earthlink.net...
my karate instructor asked the class if they understood the equation f=ma.
he led me along to say with him that if you swing (or send out) your fist
faster (thus increasing acceleration of the fist etc) the force applied
is,
by this relationship, also greater. I didn't mention that I only have
understood f=ma to mean that a mass accelerating has a certain force
acting
upon it. can this equation alone support the idea that the faster the
punch
the more forceful the blow?
F = m * a is actually only an approximation.
The truth is that f = dp/dt, that means that force equals the change of
momentum
in time (derivative) or if you want to express it in the terms of
acceleration:
F = E/(c^2) * a + v/(c^2) * dE/dt,
where E is body's energy, c - speed of light (constant),
a - acceleration, v - speed, dE/dt - change of energy over time
(derivative).
It's the equation I derived while being curious how to express
Newton II^nd law of dynamics using acceleration and not neglecting
relativistic effects.
It can be easily noticed that for small velocities from Einstain equation
(E=mc^2)
we have that m ~= E/(c^2) and term v/(c^2) is small,
so we can omit it having F = m * a.
--
Regards,
Krzysiek
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| User: "S. Enterprize Company" |
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| Title: Re: f=ma, basic physics and self-defense |
10 Dec 2003 02:07:44 AM |
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my karate instructor asked the class if they understood the equation f=ma.
he led me along to say with him that if you swing (or send out) your fist
faster (thus increasing acceleration of the fist etc) the force applied is,
by this relationship, also greater. I didn't mention that I only have
understood f=ma to mean that a mass accelerating has a certain force acting
upon it. can this equation alone support the idea that the faster the punch
the more forceful the blow?
No. A more forceful punch is when you throw your weight into the punch.
Smart's Alt. Physics News Group
http://pub39.bravenet.com/forum/show.php?usernum=3320272813&cpv=1
S. Enterprize (Science Journal)
http://smart1234.s-enterprize.com/
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| User: "sol" |
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| Title: Re: f=ma, basic physics and self-defense |
10 Dec 2003 02:39:55 PM |
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(S. Enterprize Company) wrote in message news:<20031210030744.21911.00000460@mb-m26.aol.com>...
my karate instructor asked the class if they understood the equation f=ma.
he led me along to say with him that if you swing (or send out) your fist
faster (thus increasing acceleration of the fist etc) the force applied is,
by this relationship, also greater. I didn't mention that I only have
understood f=ma to mean that a mass accelerating has a certain force acting
upon it. can this equation alone support the idea that the faster the punch
the more forceful the blow?
No. A more forceful punch is when you throw your weight into the punch.
Smart's Alt. Physics News Group
http://pub39.bravenet.com/forum/show.php?usernum=3320272813&cpv=1
S. Enterprize (Science Journal)
http://smart1234.s-enterprize.com/
To get a sense of this momentum, I have seen different perspectives
related to the martial art forms. When I looked at the orbital pattern
of mercury and the thread the "Daisey" one gets a sense of this, when
the pattern is changed and becomes like a daisey pattern.
See:
http://astrosun.tn.cornell.edu/courses/astro201/merc_adv.htm
In every oscillation, the pendulum speaks to this idea, and becomes a
measure of the pulse "frequencies" of orbiting neutron star that we
learn of in the evolution of GR. Taylor and Hulse are good examples of
the measure here.
In was in this undertanding, that if you looked up push hands(Tai Chi)
the connection bewteen two arms, senses the momentum changes and
learns to channel this back. No different then sensing in Judo, the
momentum of the assailent and using that to move forward the opponent
in the continued direction. How about using orbits of planets to
propel satelittes?
I hope you get a deeper sense of what is happening here from the
examples. Once you internalize, one does not forget.
Sol
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| User: "S. Enterprize Company" |
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| Title: Re: f=ma, basic physics and self-defense - Smart1234 Shows What Gravity Is |
10 Dec 2003 09:56:19 PM |
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smart1234@aol.com (S. Enterprize Company) wrote in message
news:<20031210030744.21911.00000460@mb-m26.aol.com>...
my karate instructor asked the class if they understood the equation f=ma.
he led me along to say with him that if you swing (or send out) your fist
faster (thus increasing acceleration of the fist etc) the force applied
is,
by this relationship, also greater. I didn't mention that I only have
understood f=ma to mean that a mass accelerating has a certain force
acting
upon it. can this equation alone support the idea that the faster the
punch
the more forceful the blow?
No. A more forceful punch is when you throw your weight into the punch.
Smart's Alt. Physics News Group
http://pub39.bravenet.com/forum/show.php?usernum=3320272813&cpv=1
S. Enterprize (Science Journal)
http://smart1234.s-enterprize.com/
To get a sense of this momentum, I have seen different perspectives
related to the martial art forms. When I looked at the orbital pattern
of mercury and the thread the "Daisey" one gets a sense of this, when
the pattern is changed and becomes like a daisey pattern.
See:
http://astrosun.tn.cornell.edu/courses/astro201/merc_adv.htm
This shows proof that the Smart Model Helix Spiral Planetary Orbital Field
is the most correct. Mercury moves in a daisy spiral field orbit around the
sun. This is due to the Helix Spiral Gravitation Field around the sun. As time
goes on, the planets move further away from the field of the sun, similarly the
way the spiral arms of a galaxy eventually move further away from the Helix
Spiral Field of a galactic core.
Einstein only saw a partial view of gravity. The Smart Stellar Model shows
the total picture. Like for example, Einstein said planets warp space causing
gravity. Then he draws this.
Einsteins partial view of gravity
________ ____________
( )
( )
O
But this is the total picture.
Smart Model Helix Spiral Field
_______ ________
( )
( )
O planet
( )
______ ( )_______
This Helix Spiral Field is the cause of gravity, which begins at the
sub-atomic level and then amplifies itself to larger scale areas in space, like
to stellar, to galactic to universal to parallel universal level.
Smart's Alt. Physics News Group
http://pub39.bravenet.com/forum/show.php?usernum=3320272813&cpv=1
S. Enterprize (Science Journal)
http://smart1234.s-enterprize.com/
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| User: "John Popelish" |
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| Title: Re: f=ma, basic physics and self-defense |
08 Dec 2003 11:02:30 PM |
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kjm wrote:
my karate instructor asked the class if they understood the equation f=ma.
he led me along to say with him that if you swing (or send out) your fist
faster (thus increasing acceleration of the fist etc) the force applied is,
by this relationship, also greater. I didn't mention that I only have
understood f=ma to mean that a mass accelerating has a certain force acting
upon it. can this equation alone support the idea that the faster the punch
the more forceful the blow?
The faster the punch, the larger the acceleration when it contacts
another object. Acceleration includes both the process of speeding up
and the process of slowing down. But it makes little difference to
the force of a punch whether you take a big swing and lots of time to
get it going, or if you snap the punch out very quickly, as long as
the punch reaches the same speed before contact. The thing that makes
the slow acceleration less effective is the time it gives recipient to
take evasive action. But the most interesting difference, for me,
between a slow and a fast punch is that a slow punch mostly pushes the
recipient, while the fast one makes expanding ripples in him, like a
rock thrown in a pond.
From this point of view, a hammer is a time machine. You apply a
modest force to it for a second or so to get it moving, but it stops
in a millisecond or so when it contacts a nail. So the force the
hammer applies to the nail is about a thousand times larger than the
force your hand applies to the hammer. A hard hammer is more
efficient than a soft one because it deforms less during the
deceleration, so must decelerate faster, creating a larger force. A
soft hammer pushes a nail, while a hard one makes a compression wave
travel down the nail that ripples it into wood like an inch worm
crawls along. There are those neat ripples, again.
--
John Popelish
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| User: "Sam Wormley" |
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| Title: Re: f=ma, basic physics and self-defense |
08 Dec 2003 10:54:18 PM |
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kjm wrote:
my karate instructor asked the class if they understood the equation f=ma.
he led me along to say with him that if you swing (or send out) your fist
faster (thus increasing acceleration of the fist etc) the force applied is,
by this relationship, also greater. I didn't mention that I only have
understood f=ma to mean that a mass accelerating has a certain force acting
upon it. can this equation alone support the idea that the faster the punch
the more forceful the blow?
http://scienceworld.wolfram.com/physics/Momentum.html
http://scienceworld.wolfram.com/physics/KineticEnergy.html
Once contact is made there ma still be some force exerted my
muscles in action.
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| User: "Varn Nine" |
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| Title: Re: f=ma, basic physics and self-defense |
09 Dec 2003 09:24:53 AM |
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kjm wrote:
my karate instructor asked the class if they understood the equation f=ma.
he led me along to say with him that if you swing (or send out) your fist
faster (thus increasing acceleration of the fist etc) the force applied is,
by this relationship, also greater. I didn't mention that I only have
understood f=ma to mean that a mass accelerating has a certain force acting
upon it. can this equation alone support the idea that the faster the punch
the more forceful the blow?
My instructor always told us we should execute punches and kicks in the
same way regardless of whether there was an oponent there or not. For
such techniques to work effectively, they must be as fast as possible.
A faster fist will locally deform the opponent, breaking bones,
rupturing soft tissue and causing general mayhem while the rest of the
opponent stays more or less where it was. A slow fist will pick the
opponent up and carry him along.
(Of course, faster techniques have the added bonus of being more
difficult to dodge in time.)
..v9
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