the force required to just move a body up the inclined plane is double the force required to just prevent the body form sliding down the plane. the coefficent of friction is µ . if θ is the angle of inclination of the plane the tan θ is equal to :a. µb. 3 µc. 2 µd. 0.5 µ

Rohan Bhatia

force required to prevent the body from sliding

F=mgsinθ-µmgcosθ

force required to just move the body up

F1=mgsinθ+µmgcosθ

it is given

F1=2f

mgsinθ+µmgcosθ=2(mgsinθ-µmgcosθ)

0r 3µmgcosθ=mgsinθ

tanθ=3µ

In the equation for force required to prevent the body from sliding - frictional force should have been opposite to the force applied? Isn`t it? Why is it in the direction of force. Pls explain

For a sliding body, it means (mgsin t) is greater than the frictional force, so the to balance it up(to make it static) you need to add up to the frictional force to make equal to the mgsin t( the resolution of the weight of the body according to the plane).So we have F +Fr = mgsin tBut It will be F= mgsin t + Fr ( for the force to move it up the plane)