A block mass $m$ is placed on a smooth wedge of inclination $\theta$. The whole system is accelerated horizontally so that the block does not slip on the wedge. The force exerted by the wedge on the block ( $g$ is acceleration due to gravity) will be:

• A

  $m g \cos \theta$
• B

  $m g \sin \theta$
• C

  $m g$
• Correct answer
  D

  $\mathrm{mg} / \cos \theta$

Solution

Here $N \cos \theta=m g$ $\Rightarrow N=\frac{m g}{\cos \theta}$

Hence, the correct answer is option: 'D'.