Assertion :If a body is momentarily at rest, it means that force or acceleration are necessarily zero at that instant. Reason: Force on a body at a given time is determined by the direction of the motion only.

Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

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Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

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Assertion is correct but Reason is incorrect

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Both Assertion and Reason are incorrect

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Solution

The correct option is D Both Assertion and Reason are incorrect
If a body is momentarily at rest i.e.v=0 at an instant, it does not mean that force or acceleration are necessarily zero at that instant. For example, when a ball thrown upward reaches its maximum height, v=0 but the force continues to be its weight mg and the acceleration is g. Force is not always in the direction of motion.

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Similar questions

Assertion (A) Order of the reaction can be zero or fractional.

Reason (R) We cannot determine order from balanced chemical equation.

(a) Both assertion and reason are correct and the reason is correct explanation of assertion
(b) Both assertion and reason are correct, but reason does not explain assertion.
(c) Assertion is correct, but reason is incorrect
(d) Both assertion and reason are incorrect
(e) Assertion is incorrect but reason is correct.

Q. Assertion : Two electrons of helium atom are placed in only one shell but three electrons of lithium need two shells.
Reason: A shell can have maximum

{2n}^{2}

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Assertion (A) Order and molecularity are same.

Reason (R) Order is determined experimentally and molecularity is the sum of the stoichimetric coeffcient of rate determining elementary step.

Q. Assertion
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Reason
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Q. Assertion : A body is moved from

x = 2

x = 1

, under a force

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, the work done by the force is negative.
Reason: Force and displacement are in opposite directions.

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