Question

A body at rest can have:
(This question has multiple answers)
A) Speed
B) Energy
C) Momentum
D) Relative velocity

Answer 1

A body at rest is the state of the body which does not move with time. Therefore, the body doesn’t change its position with time. There are many factors that depend on the body at rest and the body in motion. The body at rest doesn’t move hence it cannot have velocity. Like this there many many concepts don't apply to the resting body. According to the concept of relativity, the body at rest depends on the frame at where the body is situated.

Complete step by step answer:
(i) If the body is at rest, then its position doesn’t change with time. It remains in the same position. But the speed is the rate of distance travelled. Hence, the body at rest cannot have speed.
(ii) Energy is of two types for the particle. One is potential energy and another one is kinetic energy. Potential energy remains maximum when the body is at rest. And the kinetic energy remains zero as the velocity of the body at rest is zero. We know that the total energy in the body remains constant. Hence the total energy of the body is equal to its potential energy. Hence the body at rest has energy.
(iii) Momentum is also dependent on velocity as momentum is the product of mass and velocity. Hence the body at rest cannot have momentum,
(iv) The relative velocity of the body can be said only by knowing the frame of reference in which the body is placed. If the body is placed in the frame of reference which is moving or the observer's frame of reference is moving, then the body at rest has relative velocity. If the body at rest and observer are in the same frame of reference, then the body does not have relative velocity.

Hence, option B is only correct.

Note: Even the net force changes according to the state of an object. The terms depend on the velocity it does not possess to the body at rest. Hence the body at rest does not have velocity, acceleration, momentum, kinetic energy etc. As the potential energy in the object does not depend on the velocity hence the body at rest possesses it. As energy is the sum of potential energy and kinetic energy of an object, we can say that the resting body possesses energy.