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NEET PHYSICSRotational motionMedium

Question

A solid sphere, disc, and solid cylinder all of the same mass and made up of the same material are allowed to roll down (from rest) on an inclined plane, then:

A

solid sphere reaches the bottom first.

B

solid sphere reaches the bottom late.

C

the disc will reach the bottom first.

D

all of them reach the bottom at the same time.

Step-by-Step Solution

The acceleration of a rigid body rolling down an inclined plane without slipping is given by a=gsinθ1+K2R2a = \frac{g \sin\theta}{1 + \frac{K^2}{R^2}}, where KK is the radius of gyration. The ratio K2R2\frac{K^2}{R^2} for the given bodies are:

  1. Solid sphere: K2R2=25=0.4\frac{K^2}{R^2} = \frac{2}{5} = 0.4
  2. Disc: K2R2=12=0.5\frac{K^2}{R^2} = \frac{1}{2} = 0.5
  3. Solid cylinder: K2R2=12=0.5\frac{K^2}{R^2} = \frac{1}{2} = 0.5 Since the solid sphere has the smallest value of K2R2\frac{K^2}{R^2}, it will have the maximum acceleration (aa) among the three. Therefore, it takes the minimum time and reaches the bottom first.

Exam Context & Concepts Covered

This question aligns with the NEET PHYSICS syllabus, specifically targeting concepts from Rotational motion. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

PHYSICSRotational motionspherecylindermaterialallowedinclined

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