Question

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 motin only.
A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true and reason is the not correct explanation of assertion.
C. If assertion is true but reason is false
D. If both assertion and reason are false.

Answer 1

Correct Answer - D
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.