Which of the following statement must always be true? 1. If an objects acceleration is zero, then its speed must remain constant. 2. If an objects acceleration is constant, then it must move in a straight line. 3. If an objects speed remains constant, then its acceleration must be zero.

Which of the following statement must always be true? 1. If an ob…

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MCQ

Which of the following statement must always be true?

If an objects acceleration is zero, then its speed must remain constant.
If an objects acceleration is constant, then it must move in a straight line.
If an objects speed remains constant, then its acceleration must be zero.

A
I and III only
B
I only
C
III only
D
II and II only

✓

Answer

I only

Explanation:

Acceleration is the rate of change of speed of the object. Thus when acceleration is zero, the speed of object remains constant.

Acceleration of an object moving in a circular path is $\frac{\text{v}^2}{\text{R}}.$ Thus an object with constant acceleration may not move in a straight line.

Again in case of circular path, the speed remains same, but acceleration is finite.

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