AIIMS2017Physics-Circular Motion

AIIMS 2017 Physics Centripetal Acceleration MCQ Question

Type: MCQ-conceptual-Medium-Class 11

A stone is moved in a horizontal circle of radius 4m by means of a string at the height of 20m above the ground. The string breaks and the particles flies off horizontally, striking the ground 10m away. The centripetal acceleration during circular motion is given by

A

6.25 ms⁻²

B

12.5 ms⁻²

C

18.75 ms⁻²

D

25 ms⁻²

Correct Answer

Option A

Detailed Explanation

To find the centripetal acceleration (aₐ) of the stone in circular motion, we first determine its initial velocity (v) after the string breaks. The stone falls from a height of 20 m, taking t = √(2h/g) = √(2 × 20 m / 9.81 m/s²) ≈ 2.02 s to hit the ground. During this time, it travels horizontally 10 m, giving v = distance/time = 10 m / 2.02 s ≈ 4.95 m/s. The centripetal acceleration is then calculated using the formula aₐ = v²/r, where r = 4 m, resulting in aₐ = (4.95 m/s)² / 4 m ≈ 6.25 m/s², confirming option A. Other options are incorrect as they do not match this calculated value based on the given parameters.

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