Question

A rear side of a truck is open and a box of mass 20kg is placed on the floor of the truck at a distance of 5 m away from the open end. If the truck starts from rest and moves on a straight road with certain acceleration, the box falls off the truck after 10 seconds. The acceleration of the truck is (${\mu }_k=0.4$ and $g=10m{s}^{-2}$)

• A. $4.1m{s}^{-2}$
• B. $2.2m{s}^{-2}$
• C. $3.2m{s}^{-2}$
• D. $1.8m{s}^{-2}$

Answer 1

The correct option is A $4.1m{s}^{-2}$

Relative acceleration $a_1=a-0.4g$; where $a$ is acceleration of the truck and $0.4g$ is acceleration of box

Now, $a_1=2s/t^2;s=5;t=10\Rightarrow a_1=0.1$

So, $a=4+0.1=4.1m{s}^{-2}$