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

Answer 1

Wt. of box = 20 N.

Fp1 = 4*Cos20 = 3.76 N. = Force acting Parallel to ramp(upward).

Fp2 = 20*sin A = Force acting parallel to ramp(downward).

Fp2-Fs-Fp1 = 0.
20*sin A-5-3.76 = 0. Equilibrium.
A = ?.

9
20*sin A-5-3.76 = 0.
20*sin A = 8.76,
A = 10.8o. = Angle of elevation.