The first of two identical boxes of mass m is sitting on level ground. The second box is sitting on a ramp that makes a 20° angle with the ground. The normal force of the level ground on the first box is N_L; the normal force of the ramp on the second box is N_R. Which statement is correct? A) N_R = N_L = mg. B) N_L = mg; N_R = mg sin 20°. C) N_L = mg; N_R = mg cos 20°. D) N_L = mg; N_R = −mg cos 20°. E) N_R = −N_L = −mg.

Question

Quizplus · Accepted Answer

For the box on level ground, the normal force equals the gravitational force acting on it, which is mg. For the box on the ramp, the normal force is the component of the gravitational force perpendicular to the surface of the ramp, which is mg cos(20°).

The First of Two Identical Boxes of Mass M Is