BITSAT 2025 | Rotational Motion Question 1 | Physics

A man with a mass of 80 kg is standing on the rim to a circular platform with a mass of 200 kg . The circular platform is rotating at 12 revolutions per minute (rpm) about its axis. The man moves from the rim towards the centre of the platform. The new angular velocity of the system will be (Assuming that the man's moment of inertia at the centre of the plateform is negligible)

10 rpm

12 rpm

21.6 rpm

zero

BITSAT 2024

MCQ (Single Correct Answer)

-1

The moment of inertia of a cube of mass $ m $ and side $ a $ about one of its edges is equal to

$ \frac{2}{3} m a^{2} $

$ \frac{4}{3} m a^{2} $

$ 3 m a^{2} $

$ \frac{8}{3} m a^{2} $

BITSAT 2024

MCQ (Single Correct Answer)

-1

A rigid body rotates about a fixed axis with variable angular velocity equal to $ \alpha-\beta t $, at the time $ t $, where $ \alpha, \beta $ are constants. The angle through which it rotates before it stops is

$ \frac{\alpha^{2}}{2 \beta} $

$ \frac{\alpha^{2}-\beta^{2}}{2 \alpha} $

$ \frac{\alpha^{2}-\beta^{2}}{2 \beta} $

$ \frac{(\alpha-\beta) \alpha}{2} $

BITSAT 2023

MCQ (Single Correct Answer)

-1

Two rings of radius $$R$$ and $$n R$$ made of same material have the ratio of moment of inertia about an axis passing through centre is $$1: 64$$. The value of $$n$$ is

2$$\sqrt2$$

1/2

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