The rear side of a truck is open and a box of mass 20kg is placed on the truck 4 meters away from the open end coofficent of friction between truck and block is 0.15 the truck starts from rest with an acceleration of `2m//sec^(2)`on a straight road The box will fall off the truck when truck is at a distance from the starting point equal to`(g=10m//s^(2))`

Options

A. 4metres
B. 8 metres
C. 16 metres
D. 32metres

Answer

C

Explanation

`fs_(max)=mumg`
` 0.15xx20xx10`
`30N`
`a_(block)=30/20=3/2m//s^(2)`
` a_(truck)=2m//s^(2)`
`a_(rel)=1/2m//s^(2)`
` d=1/2a_(rel)t^(2)`
`4=1/2xx1/2xxt^(2)`
`t=4sec`