Imagine that you are hovering next to the space shuttle in an Earth orbit. Your buddy of equal mass, who is moving at 8 km/h with respect to the shuttle, bumps into you. If he holds onto you, how fast do you both move with respect to the ship?
2007-01-30 10:02:38 · 5 answers · asked by Jane A 3 in Science & Mathematics ➔ Physics
4 km/h for both moving with respect to the ship.
2007-01-30 10:12:58 · answer #1 · answered by chanljkk 7 · 0⤊ 0⤋
Conservation of momentum
The principle of conservation of momentum states that the total momentum of a closed system of objects (which has no interactions with external agents) is constant. One of the consequences of this is that the centre of mass of any system of objects will always continue with the same velocity unless acted on by a force outside the system.
Conservation of momentum is a consequence of the homogeneity of space.
In an isolated system (one where external forces are absent) the total momentum will be constant: this is implied by Newton's first law of motion. Newton's third law of motion, the law of reciprocal actions, which dictates that the forces acting between systems are equal in magnitude, but opposite in sign, is due to the conservation of momentum.
Since momentum is a vector quantity it has direction. Thus, when a gun is fired, although overall movement has increased compared to before the shot was fired, the momentum of the bullet in one direction is equal in magnitude, but opposite in sign, to the momentum of the gun in the other direction. These then sum to zero which is equal to the zero momentum that was present before either the gun or the bullet was moving.
[edit] Conservation of momentum and collisions
Momentum has the special property that, in a closed system, it is always conserved, even in collisions. Kinetic energy, on the other hand, is not conserved in collisions if they are inelastic. Since momentum is conserved it can be used to calculate unknown velocities following a collision.
2007-01-30 18:13:35 · answer #2 · answered by scientific_boy3434 5 · 0⤊ 0⤋
It's a (M1)(V1) = (M2) (V2) problem...but since he held on the equal part would be combined...so one mass and one velocity. Hope this rings a bell..we did this chapter weeks ago..so i forgot.
2007-01-30 18:07:42 · answer #3 · answered by da_boogie_man76 1 · 0⤊ 0⤋
equal but opposite reaction
2007-01-30 18:12:21 · answer #4 · answered by sphsgolfer 1 · 0⤊ 0⤋
4km/h
2007-01-30 18:11:18 · answer #5 · answered by Clown Knows 7 · 0⤊ 0⤋