Physics - Rotation Question with Solution | TestHub

PhysicsRotationTorque / angular accelerationMedium2 minQB

PhysicsMediummultiple choice

A uniform rod kept vertically on the rough ground falls from rest. Its foot does not slip on the ground. Then :-

Answer:

B, C, D

Solution:

Torque about the foot:

$m g \frac{L}{2} sin θ = \frac{m L ^{2}}{3} α$

$α = \frac{3}{2} \frac{g s i n θ}{L}$

Tangential acceleration of a point at distance r is $r α$

For the top end, r = L and sin θ = 1:

$a_{t} = \frac{3 g}{2} = 1.5 g$

This is more than g, so (A) is wrong

Accelerations depend on r and θ, so (B) and (C) hold

Answer: B, C, D

Stream:JEESubject:PhysicsTopic:RotationSubtopic:Torque / angular acceleration

⏱ 2mℹ️ Source: QB

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