Question

The body moving with uniform velocity will be always in equilibrium. The statement
A. true
B. false
C. ambiguous
D. cannot say

Answer 1

Hint:When a body is moving with uniform velocity it means the net change in the velocity with respect to time is zero. The rate of change of velocity \[\left( \text{m/s} \right)\] is the acceleration \[\left( \text{m/}{{\text{s}}^{2}} \right)\] of the body which is zero here. So the net force on the moving body will be zero.

Complete answer:
Velocity is the rate of change of displacement. The rate of change of velocity is defined as acceleration. But when a body is moving with uniform or constant velocity then acceleration of the body will be zero. At this time there will be no force on the body as we know force is the product of mass of a body to the acceleration of the body. So the net force on the body is zero, which means the body is in equilibrium and the body will remain in equilibrium when the forces (and torques) applied on the body are zero either it is in the rest or moving with constant velocity.

Therefore, the correct choice is: (A) true.

Note:
At rest means velocities vanish; at equilibrium means forces (and torques) vanish. Newton's second law implies that If forces (and torques) vanish, velocity does not change means the body will be in motion with uniform velocity.