Three identical balls are traveling north with speed v. Each experiences a collision, as follows:
Ball A travels with speed v south after its collision.
Ball B is at rest after its collision.
Ball C travels with speed v east after its collision.
Rank the three balls based on the magnitude of the impulse (change in momentum) they experience, from largest to smallest.
For A>C>B
The change in momentum for A is twice that of B because it goes from +p to -p. B just goes from +p to 0. The change in momentum of C lies somewhere inbetween these two answers.
For A=C>B
since the ball moved at the same speed after the collsions a nd c so it should have been stuck with the same force, but at a different angle. The collision b was not strong enough to make the ball move afterwards, therefore it should be less.
For A>B>C
A's change is the greatest because it is going mv initially and then -mv final, so there's a total change of -2mv. B's change in momentum is -mv because its final mv is zero, so final minus initial means the change is a -mv. C's change is the least because although it changes direction, it does not go in a negative direction, so there is nothing that states a change in velocity. Therefore, the final mv minus the initial mv is zero for C.
For B>A=C
Momentum = Mv For ball A and C, the speed has not changed, only the direciton has changed. Therefore, momentum before is equal to momentum after. However, for gall B, it does not move after the collision, so v = 0 => momentum = 0. Impulse = Change in momentum So, for ball B, impulse = mv and for ball A and C, impulse = mv-mv = 0