> [WS:] This is what I thought too, but I was not sure.
> But besides the oxygen issue, how much propulsion
> would you get on a 200 mile trip? The moon has some
> gravity, so one cannot levitaate like in a zero
> gravity condition - just make longer jumps (6 times
> longer than on Earth, if memory serves.) Firing 12 or
> so shots may add to the length of 12 jumps, but that
> is a small part of a 200 mile journey, no?
Sure, I'll do your physics homework for you. :-P
The law we care about is Newton's Third: For Every Action, There Is An Equal And About Reaction.
So, we need to calculate the Force of the bullet to then apply it to the mass of astro-shag to calculate how it accelerates her.
Let's take a GI 1911 model .45 ACP, with 7 rounds in each clip and one in the chamber (astro-shag is locked and loaded to presumably fight off moon-monsters). A 10.7 g bullet has a muzzle velocity of 320 m/s. We will use kinematics formula relating muzzle velocity, acceleration, and barrel length (5 in):
v^2 = v0^2 + 2as
for v0 at rest, is:
a = v^2/2s = 4.03 * 10^5 m/s^2
Force is then:
F = m a = 43 * 10^2 kgm/s^2
Let's say astro-shag is 120 lbs and wearing 80 lbs of gear, making the whole package 200 lbs, or about 90 kg. Again using the above equation:
a = F / m = 47.9 m/s^2
Back to kinematics:
a = v^2/2s
Using the above acceleration and the 5" barrel length we can calculate astro-shag's velocity after the bullet has left the gun:
3.49 m/s
Astro-shag recalls from physics that with no air resistance, she can expect to move in a perfect parabola, and range is maximum when horizontal and vertical velocity are equal; i.e. she fires the gun at exactly 45 degrees. Derivation is left as an exercise for the reader, but range:
R = v^2/g
where g is the gravitational acceleration on the moon, which is 1.62m/s^2. That makes astro-shag's maximum range from firing the gun 7.52 meters. If she could fire all 16 rounds consecutively she could go 120 meters, which would be handy for crossing a chasm or some other precarious terrain.
Corrections welcome; I did not check my work.
Matt
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