Question

A body is kept on a frictionless inclined surface with angle of inclination $\alpha$. the incline is given an acceleration $a$ to keep the block stationary. Then $a$ is equal to :

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

Answer 1

The correct option is D $g\tan \alpha$

From FBD, the block will remain stationary on the incline plane if $ma\cos \alpha =mg\sin \alpha$
$\therefore a=\frac{g\sin \alpha }{\cos \alpha }=g\tan \alpha$
Ans:(D)