Question

A block is kept on a frictionless inclined surface with angle of inclination $\alpha$ as shown in figure. The incline is given an acceleration $a$ to keep the block stationary. Then $a$ is equal to

• A. $g \tan \alpha$
• B. $g$
• C. $g {cosec} \alpha$
• D. $\frac{g}{\tan \alpha}$

Answer 1

Answer: (A)

The incline is given an acceleration $a$. Acceleration of the block is to the right. Pseudo acceleration $a$ acts on the block to the left. As it is clear from figure, the block will remain stationary, when
$m a \cos \alpha=m g \sin \alpha$ or $a=\frac{g \sin \alpha}{\cos \alpha}=g \tan \alpha$