MCQ
Assertion $(A)$ : If a particle is moving with constant velocity, then the average velocity for any time interval is equal to instantaneous velocity.
Reason $(R)$ : If average velocity of a particle moving on a straight line is zero for a given time interval, then instantaneous velocity at some instant within this interval may be zero.
  • A
    Both $A$ and $R$ are true and $R$ is the correct explanation of $A$.
  • Both $A$ and $R$ are true but $R$ is not the correct explanation of $A$
  • C
    $A$ is true but $R$ is false
  • D
    $A$ is false but $R$ is true

Answer

Correct option: B.
Both $A$ and $R$ are true but $R$ is not the correct explanation of $A$
Both $A$ and $R$ are true but $R$ is not the correct explanation of $A$.
Explanation: Average velocity $ V _{ av }$
$=\frac{\text { Total displacement }}{\text { Total elapsed time }}=\frac{V t}{t}= V $
$=$ Instantaneous velocity
Hence, assertion is correct. If a particle is in a round trip on a straight line,
then average velocity is zero but at the instant atwhich the particle reverses its direction of motion, velocity is zero.
So, reason is correct. But reason is not the correctexplanation of assertion.

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