Question

Acceleration of a body can be zero when
(This question has multiple correct options)
(A) No force is acting on it
(B) One force of infinite magnitude is acting on it
(C) Multiple forces are acting on it
(D) Can never be zero

Answer 1

Hint: Acceleration can be defined as the rate of change of velocity with respect to time. Acceleration, since it has both magnitude and direction, is a vector quantity. It is also the second position derivative with respect to time, or it is the first velocity derivative with respect to time.

Complete Step-by-Step Solution :
We need to discuss Newton's laws of motion in order to answer this question. We understand that the first law of Newton states that the body in motion remains in motion until and unless an external force acts upon it to change its direction.
Also, unless and until applied force is not applied to move it, the body in the rest position stays in the rest position.
We also understand Newton's second law of motion, which states that the acceleration generated in the body is proportional to the acceleration produced by the applied force.
From the above equation, when no force acts on the body, the acceleration of the body must be zero.
So, option (A) is correct.
If a single force of infinite magnitude acts on the body, we can say that, according to Newton's second law of motion, the body must accelerate.
So, option (B) is correct.
If we have two forces of the same magnitude, but acting on the body in the opposite direction, these forces will cancel out and zero will be the net force on the body. We can therefore say that the acceleration of the body must be zero, according to Newton's second law of motion.
So, the (C) option is correct.
In uniform motion, if we have the body moving, its velocity does not change with time. In that case, the body's acceleration is zero.
So, option (D) is incorrect.

Hence, option (A.), (b.), and (C.) are correct.

Note: If the object's velocity is constant with respect to time, the body therefore experiences zero acceleration. Hence the slope of the velocity-time curve is \[0\].