Single Choice

The velocity of a particle is zero at $$t = 0$$

AThe acceleration at $$t = 0$$ must be zero
Correct Answer
BThe acceleration at $$t = 0$$ may be zero
CIf the acceleration is zero from $$t = 0$$ to $$t = 10\ s$$ , the speed is also zero in this interval
DIf the speed is zero from $$t = 0$$ to $$t = 10\ s$$ the acceleration is also zero in this interval

Solution

Options B,C,D are correct.
A) It is not true.Consider the case of a particle dropped vertically downward from some height.Its velocity at t=0 is zero but acceleration is not zero .It is equal to "-g".
B) It is true because we do not have information about the velocity in next instant.If in next instant velocity still remains zero,the acceleration will be zero.
C) It is true because if acceleration is zero that means there is no change in velocity.so,velocity remains zero in this interval.
D) It is true because if speed remains zero for this interval,it means the particle is at rest.so,acceleration is also zero for this interval.

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