physics
posted by Heart .
A 0.200 kg plastic ball moves with a velocity of 0.30 m/s. It collides with a second plastic ball of mass 0.100 kg, which is moving along the same line at a speed of 0.10 m/s. After the collision, both balls continue moving in the same, original direction. The speed of the 0.100 kg ball is 0.26 m/s. What is the new velocity of the 0.200 kg ball?
GIVEN:
plastic ball m = 0.200 kg
v = 0.30 m/s
m = 0.100 kg
v = 0.10 m/s
I know the mass doesn't change but the velocity changed for the second ball which is 0.26 m/s. Is this one of those problems with before colliding and after colliding.

This is a conservation of momentum problem. You know the masses and velocities of both balls before impact. The masses do not change. Your only unknown in the final velocity of one ball, and you can solve for that with the conservation of momentum equation (for motion along one axis only)

no