Question

A body is sliding down a rough inclined plane. The coefficient of friction between the body and the plane is $0.5$. The ratio of the net force required for the body to slide down and the normal reaction on the body is $1:2$. Then, the angle of the inclined plane is

• A. ${15}^0$
• B. ${30}^0$
• C. ${45}^0$
• D. ${60}^0$

Answer 1

Answer: (C)

${45}^0$

Force required to slide down is: $F=-\mu mgcos\theta +mgsin\theta$

$N=mgcos\theta$

Now $\frac{F}{N}=\frac{1}{2}=\frac{-0.5mgcos\theta +mgsin\theta }{mgcos\theta }$

$tan\theta =1\Rightarrow \theta ={45}^o$