Q: The force required to just move a body up the inclined plane is double the force required to just prevent the body from sliding down the plane. The coefficient of friction is μ . If θ is the angle of inclination of the plane than tanθ is equal to

(a) μ

(b) 3μ

(c) 2μ

(d) 0.5μ

Ans:(b)

m(gsinθ + μgcosθ) = 2m(gsinθ – μ gcosθ)

3μcosθ = sinθ

tanθ =3 μ