posted on Feb, 23 2012 @ 06:39 PM
reply to post by usmc0311
Presuming you are standing on the surface of a planet, or other celestial body, the rules of gravity will influence a projectile same as on
Earth....just, different rates of gravitational acceleration.
The (fictitious) example of the Moon mentioned above, for example: Just as on Earth, if you fire a bullet from a gun that is perfectly parallel to
the surface (and assuming a perfectly flat surface....no obstructions), and dropped a bullet from the same height as the barrel of the projectile, so
that it free fell....both bullets will hit the ground at the same time.
The bullet in motion will describe an arc, but will still drop vertically a the same rate as the bullet being dropped.
On the Moon, the difference is in the (slightly) longer time it takes to drop, due to the lower acceleration due to gravity....so the bullet being
fired will travel farther as a result.
If you were somewhere with VERY light gravity (medium-sized asteroid, for example) (and all of this ignores effects of any atmospheric drag, of
course).....in a very low-G situation, the bullet you fire could theoretically exceed the escape velocity of the body itself....thus, that bullet
would never fall back down, but would continue on a trajectory....even if it would follow a trajectory in an arc, as influenced by whatever gravity
Counter-intuitive, but just physics.