Given below are two statements: one is labelled as Assertion (A) and other is labelled as Reason (R).
Assertion (A): At highest position in a vertical circular motion, tension in the string is minimum.
Reason (R) : At the highest point, the tension = centrifugal force - weight of body. This is the minimum value for tension throughout the motion.

Correct option is A

The correct answer is (a) Both (A) and (R) are correct and (R) is the correct explanation of (A)

Explanation:
• In vertical circular motion, at the highest point, both tension (T) and weight (mg) act downwards.
• $T + mg = \frac{mv^2}{r}$ (centripetal force).
• Rearranging, $T = \frac{mv^2}{r} - mg$. Since weight opposes the centripetal requirement here, tension is at its minimum.
• At the lowest point, $T = \frac{mv^2}{r} + mg$, which is maximum.

Information Booster:
• For the body to complete the circle, the minimum velocity at the top must be $\sqrt{gr}$.
• At this critical velocity, tension at the top becomes zero.

Additional Knowledge:
(A) correct but (R) incorrect (Option b)
• Incorrect because the formula in (R) correctly explains the physics of (A).
(A) incorrect (Option c)
• Incorrect as tension is mathematically proven to be lowest at the top.
None (Option d)
• Incorrect as the physics is sound.

So the correct answer is (a)