Physics - NLM Question with Solution | TestHub

Weight is the gravitational pull of the earth on the body; the normal force is the contact force from the surface. They are different in nature and generally different in magnitude (e.g. on an incline, or in an accelerating lift).

(A) incorrect - they are not the same thing. (B) incorrect - they do not always have the same magnitude (N = mg only on a horizontal surface with no vertical acceleration or extra vertical forces).

(C) incorrect - an action-reaction pair acts on two different bodies; the normal force and weight both act on the same body, so they cannot be an action-reaction pair. (The reaction to the normal force is the body pushing the surface down; the reaction to weight is the body pulling the earth up.)

(D) correct statement - in the special case of rest on a horizontal surface with no other vertical forces, N = mg.

Incorrect statements: (A), (B), (C).

$$\mathrm{N}>\mathrm{mg}$$