question_answer

Car is accelerating with acceleration = 20 m/s2. A box of mass m = 10 kg that is placed inside the car it is put in contact with the vertical wall of car as shown. The friction coefficient between the box and the wall is \[\mu =0.6\].

A) The acceleration of the box will be \[10\,m/{{\sec }^{2}}\]

B) The friction force acting on the box will be 100 N

C) The contact force between the vertical wall and the box will be 100 N

D) None of these

Correct Answer: B

Solution :

The breaking force is insufficient, so the block will not slide.

So friction force = 100 N

and acceleration will be \[20\,m/{{\sec }^{2}}\]only

Net contact force on the block

\[=\sqrt{{{\left( 200 \right)}^{2}}+{{\left( 100 \right)}^{2}}}\,=\,100\sqrt{5\,}\,N\]