Question

A block 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 $\alpha$ is equal to

(AIEE 2005)

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

Answer 1

The correct option is A

g tan $\alpha$

Resolving along the plane and perpendicular to it.

$\therefore$ mg sin $\alpha$ = m $\alpha$ cos $\alpha$

$\Rightarrow$ a = g tan $\alpha$