A wooden block rests on a rough inclined plane

PHYSICS · Single correct · A Level · Physics · Mechanics and materials · Mechanics and materials

Problem

A wooden block rests on a rough inclined plane. The coefficient of static friction between the block and the plane is

\mu_s = 0.40

. At what approximate angle

\theta

(with the horizontal) will the block be just on the point of sliding down? (a)

38^{\circ}

(b)

22^{\circ}

(c)

66^{\circ}

(d)

68^{\circ}