A box sitting on a flat surface has a coefficient of static friction of s = 0.3. If one end of the surface is

A box sitting on a flat surface has a coefficient of static friction of μ_s = 0.3. If one end of the surface is raised, static friction prevents the box from sliding until the force of static friction is overcome. The critical angle at which the box begins to slide, θ_c, can be found from the equation tan θ_c= μ_s.

(a) What is the critical angle for the box?

(b) If the box is 5ft from the pivot point, at what height will the box begin to slide? See the figure.

Pivot point 0 5 1