Question

When can a body move with zero acceleration? Represent the condition with a velocity time graph.

Answer 1

This question is based on the concept of acceleration and velocity graphs. Velocity of a body is the rate of change of displacement and the acceleration of a body is the rate of change of velocity. Velocity time graphs are very important components of physics and are used in solving various problems related to mechanics.

Complete answer:
Any phase in which the velocity increases is referred to as acceleration. Since velocity has both a speed and a direction, you can only accelerate in one of two ways: change your speed or change your direction—or both. If you're not shifting your pace or course, you can't really accelerate—no matter how fast you're going.

In a vehicle, you can accelerate by pressing the gas pedal or braking, which both result in a shift in speed. However, you could adjust your direction of motion by turning the steering wheel. Since they shift velocity, each of these will be called an acceleration.
$a = \dfrac{{dv}}{{dt}}$
Acceleration of an object can be zero when it is moving with a constant velocity. Since velocity is constant, there will be no change in velocity and so there will be no acceleration.

The above graph represents zero acceleration.

Note: An object will accelerate if acceleration is in the same direction as velocity. The object will slow down if the acceleration is in the opposite direction of the velocity. For example, for a body thrown upwards, acceleration due to gravity slows down the body, and for an object falling freely, acceleration due to gravity increases the velocity of the body.