Question

An object of mass $5kg$ is kept on a smooth inclined plane of inclination ${30}^o$. What minimum force $F_a$ as shown in figure must be applied that would just make the block to move up the plane ?

(take $g=10m{s}^{{}^{-2}})$

• A. 25 N
• B. 50 N
• C. $25\sqrt{3}N$
• D. $\frac{50}{\sqrt{3}}N$

Answer 1

Answer: (D)

$\frac{50}{\sqrt{3}}N$

The force acting on the object due to gravity for sliding down is $mgsin\theta$ which is equal to 25 N here.
now, the component of the horizontal force $F_a$ along the incline plane should be equal to 25 N. For that,
$F_{a}cos30°=25$

$F_a$=$\frac{50}{\sqrt{3}}$ N