The rear side of a truck is open and a box of mass `2 kg` is placed on the truck `8 meters` away from the open end. `mu = 0.1` and `g = 10 m//s^(2)`. The truck starts from rest with an acceleration of `2 m//s^(2)` on a straight road. The box will fall off the truck when it is at distance from the starting point equal to

Options

A. `4 m`
B. `8 m`
C. `12 m`
D. `16 m`

Answer

D

Explanation

`ma - mu mg = ma_(0)`
`a_(0) = a - mu g = 2 - 0.1 xx 10 = 1 m//s^(2)`
`8 = (1)/(2) a_(0) t^(2) = (1)/(2) xx 1 xx t^(2) rArr t = 4 s`
The block will fall off the truck after `4s`.
Truck : Distance travelled by the truck in this time
`s = (1)/(2) at^(2) = (1)/(2) xx 2 xx (4)^(2) = 16 m`