Question

What does Newton’s third law states?

(a) The rate of change of momentum is equal to the force applied

(b) For every reaction, there is an opposite reaction

(c) The body tends to be rotated if the force is applied tangentially

(d) The body is rest until a force is applied

I got this question in exam.

My question is from Conditions for a Rigid-Body Equilibrium in division Equilibrium of a Rigid Body of Engineering Mechanics

Answer 1

Right answer is (b) For every reaction, there is an opposite reaction

The explanation: The requirement of the third law is important in the equilibrium of the body. Especially the rigid bodies. The rigid body particles are in the equilibrium and are thus facing the forces and to be in the equilibrium they also react and apply the opposite force and thus the third law of Newton.