Question

A box slides down a ${45}^o$ ramp, where the coefficient of friction between the box and the incline is given by ${\mu }_k=0.8$. The box has mass $1.6kg$.
As it slides, how much total force does the box exert on the incline?

• A. $8.9N$
• B. $11.1N$
• C. $12.7N$
• D. $14.2N$
• E. $15.7N$

Answer 1

The correct option is D $14.2N$

The normal reaction exerted by box on the incline=$N=\mu mgcos\theta$

The force of friction acting on plane=$f=\mu N$

Hence the total force acting=$\sqrt{f^2+N^2}=14.2$ newton