JAMB Physics 1990 Question 11

A body of mass 10 kg rests on a rough inclined plane whose angle of tilt θ is variable. θ is gradually increased until the body starts to slide down the plane at 30°. The coefficient of limiting friction between the body and the plane is

1. A.0.30
2. B.0.50
3. C.0.58
4. D.0.87