posted by Christina on .
Here's the question:
A 55 kg swimmer is standing on a stationary 235 kg floating raft. The swimmer then runs off the raft horizontally with a velocity of +4.3 m/s relative to the shore. Find the recoil velocity that the raft would have if there were no friction and resistance due to the water.
I THINK I'm supposed to use this equation: 0=(mAvA)+(mBvB)
But I'm not really sure.
Also I think the answer is supposed to include a direction?
momentum before = 0
momentum after = 55 * 4.3 + 235 * v
momentum after = momentum before so
236.5 + 235 v = 0
v = -1 meter/second