Question

a train moves in north direction with a speed of 54 km per hour and a monkey running on the roof of the train against its motion with a velocity of 18 km per hour with respect to the train then the velocity of Monkey as observed by a man standing on the ground is

Answer 1

The monkey is moving against the motion of the train.

It is like a boat being rowed against the current.

That is speed upstream.

Speed upstream should always be less than the speed of the stream given that one experiences resistance.

To get the relative speed we :

Get the speed of the stream minus the speed of the boat.

In our case we get the speed of the train minus the speed of the monkey.

Therefore :

Relative speed of the monkey:

= 54 - 18 = 36

The relative speed of the monkey as observed by a man standing on the ground is :

36km/h

Answer 2

Explanation:

velocity of. monkey w.r.t train. =-18km/hr=-5m/s. v elocity of train. =54km/hr=15m/s A.to relative. motion. Vm/t= Vm-Vt. = -5 m/s=Vm -15m/sVm=(-15+5 )m/s= Vm= -10m/s -sign indicates direction north. because. train is. moving in. north direction. and. have also -ve velocity