Question

A student with a mass of 65 kg steps on an improvised raft. He then moves at a speed of 2.0 m/s to cross a flooded street. With what velocity does the raft move assuming it has a mass of 25 kg?​

Answer 1

Answer: 0.2 m/s

Explanation:

The student steps on the raft, and then he moves (with the raft) at a speed of 2.0m/s to cross the flooded street.

Then the raft moves with him, at the same speed (notice that the mass of the raft does not matter, suppose that you move at 100km/h in a small car, the speed of the vehicle would be exactly the same as if you where in a truck moving at 100km/h)

Then the speed of the raft is also 2.0 m/s.