Question

A car is moving with a constant speed of $70{\text{ }}\dfrac{{km}}{h}$, which of the following statements is CORRECT?
A. The acceleration of the car is definitely zero
B. The car has an acceleration only if it is moving along a curved path
C. The car may have acceleration even if it is moving along a curved path
D. None of the above

Answer 1

In the given question it is mentioned that the car is moving with a constant speed. Constant speed refers to the speed which does not change with respect to time. Acceleration is defined as the time rate of change of speed or velocity. Hence, we have to analyze every option and hence find the answer from the given options below.

Complete answer:
Speed is defined as the distance covered by a moving body within a certain period of time.And acceleration is defined as the rate of change of speed or velocity of the moving body. It is mentioned in the question that the car is moving at a constant speed of $70{\text{ }}\dfrac{{km}}{h}$.

So the speed of the car does not change with time as the speed is constant.So, the linear acceleration of the car is zero. If the car is moving in a curved path then, both linear acceleration and angular acceleration is present.So, if the speed remains constant then the linear acceleration becomes zero but the car possesses angular acceleration and hence it moves in a curved path.

Therefore, the correct option is B.

Note: It must be noted that angular acceleration of a body depends upon angular speed. It is not mentioned in the question that the speed here is angular speed so we consider it as linear speed. But with constant speed the linear acceleration will always be zero.