A 40-kg skater travelling at 4m/s overtakes a 60-kg skater traveling at 2m/s in the same direction and collides with him.

a. If two skater remains in contact, what is their final velocity?

b. How much kinetic energy is lost?

1 answer

(a) conserve momentum:
40*4 + 60*2 = (40+60)v

(b) calculate KE = 1/2 mv^2 before and after the collision