Question

A 50-g ball collides elastically with a 290-g ball that is at rest. If the 50-g ball was traveling in the positive x-direction at 4.75 m/s before the collision, what are the velocities of the two balls after the collision?

290-g ball: magnitude m/s ?

50-g ball: magnitude m/s ?


How do I do this? :/

Answer 1

u1=(m1+m2)•v1/(m1+m2)
u2=2•m1•v1/(m1+m2)

Answer 2

I don't understand what I am doing wrong

I plugged in for the 1st one:

(.05+.290)(4.75)/(.05+.290)


and for second one:

2(.290)(4.75)/(.05+.290)

but I get wrong answers!