| Topic: |
Science > Physics |
| User: |
"Sam Wormley" |
| Date: |
23 Mar 2006 01:36:36 PM |
| Object: |
Re: Is it possible to Accelerate in Space |
Srinidhi wrote:
Although I do know that it is possible to travel in space, my friend
and I had a disagreement on the subject of whether or not it is
possible to accelerate in space. According to him, because space is a
vacuum, accleration can't take place. Only the initial takeoff speed
powers the whole course. Is this true or not. Along with that, could
you provide some reasons or evidence?
Let's take this to sci.physics.
Newton's second law... works all over the universe.
Rockets work in space... The initial take off velocity
is hardly anything compared to the velocities achieved
when the fuel is finally used up... in space.
.
|
|
| User: "The Ghost In The Machine" |
|
| Title: Re: Is it possible to Accelerate in Space |
25 Mar 2006 06:59:34 PM |
|
|
On Thu, 23 Mar 2006 19:36:36 +0000, Sam Wormley wrote:
Srinidhi wrote:
[quoted text muted]
Let's take this to sci.physics.
Newton's second law... works all over the universe.
Rockets work in space... The initial take off velocity is hardly
anything compared to the velocities achieved when the fuel is finally
used up... in space.
Depends on a fair number of factors, such as multistaging. If I'm not
mistaken the mass of the fuel tank is about 3% of the mass of the fuel in
a single-stage rocket, minimum; this means that, in Tsiolkovski's
Equation, one gets
v_f = v_e * log(100/3) = 3.5066 * v_e
If one assumes a 5% mass ratio the factor drops to 2.9957; 10% gets one
2.3026.
Of course Tsiolkovski's Equation is easily derived from the Second Law,
which can be expressed
F = ma = m dv
which together with the conservation of momentum yields
0 = m_r dv + v_e * dm
or some such. Ultimately one gets v_f = v_i + v_e * log(M_i/M_f).
--
#191,
It's still legal to go .sigless.
.
|
|
|
|
|
Related Articles |
|
|
