A box weighing 20 N, resting on a ramp, is kept at equilibrium by a 4N force at an angle of 20 degrees to the ramp, together with a friction force of 5N, parallel to the surface of the ramp. Determine the angle of elevation of the ramp.

Answer 1

gravitational force component down ramp = 20 sin A

force up ramp = 4 cos 20 + 5
so
4 cos 20 + 5 = 20 sin A