Question

ans this one also plz with reason...

Answer 1

To conserve the momentum, trolly will move in the direction opposite to man's movement.

let trollys velocity is v and its mass is m. Let man's velocity is V and his mass is M, then we have

m×v = -(M+m)×V..................(1)

we have m = 320 kg, M=80 kg, V=1m/s

by substituting this values in (1), we get v = -0.2 m/s.

Since man has moved for 4 s, distance moved by troly -0.2×4 = -0.8 m

man has moved 4 m but trolly has moved 1 m in opposite direction.

hence displacement of man with respect to ground is 4-0.8 = 3.2 m