A trolley filled with sand is moving with a velocity v on a smooth horizontal surface due to inertia. If the sand falls off at the rate of `mu kg//sec`, the velocity of the trolley as a function of time will be best represented by:

Options

A.
B.
C.
D.

Answer

D

Explanation

Since the horizontal surface is smooth, the sand particles will continue to move with same, velocity. (The ejected mass will not exert any force on the trolley, therefore its velocity will not change)
`Mv=(M-mut)v'+mu tv`
`rArr v'=v` (v' being the speed of trolley at any time t')
Hence velocity of trolley remains constant.