A man of mass $60 k g$ is standing on a boat of mass $140 k g$ , which is at rest in still water. The man is initially at $20 m$ from the shore. He starts walking on the boat for $4 s$ with constant speed $1.5 m / s$ towards the shore. The final distance of the man from the shore is:

Question

Q. A man is standing on a boat in still water. If he walks towards the shore, the boat will :

Answer 1

The man moves with a speed of 1.5 m/sec for 4 sec. So distance traveled by the man during this time period is 6 m. Let us assume the shore is to our left when he moves towards the shore there will be a relative displacement of the boat towards the right. So the relative displacement of boat is = md/(M+m), where m is mass of man ,and d is the distance he walks towards the shore and M is the mass of boat .after substituting the values given we get the relative displacement to be1.8m.so the total distance from the shore is = initial distance from the shore – distance walked by the man + relative displacement of boat = 20-6+1.8=15.8m

Answer 2

So that the option A is correct

A man of mass 60 kg is standing on a boat of mass 140 kg, which is at rest in still water. The man is initially at 20 m from the shore. He starts walking on the boat for 4 s with constant speed 1.5 m/s towards the shore. The final distance of the man from the shore is:

A man of mass $60 k g$ is standing on a boat of mass $140 k g$ , which is at rest in still water. The man is initially at $20 m$ from the shore. He starts walking on the boat for $4 s$ with constant speed $1.5 m / s$ towards the shore. The final distance of the man from the shore is: