A block rest on a rough inclined plane as shown in fig. A horizontal force F is applied to it (a) Find out the force of reaction, (b) Can the force of friction be zero if yes when? And (c) Assuming that fricition is not zero find its magnitude and direction of its limiting value.

Explanation

(a) `N=mg cos theta+ F sin theta`
(b) Yes, if mg `sin theta=F cos theta`
(c) `f=muR=mu(mg cos theta+F sin theta)`, up the plane if the body has tendency to slide down and down the plane if the body has tendency to move up.