The angular acceleration of a simple pendulum at an angle α from the vertical is proportional to
tan α
sin² α
sin α
sin 2α
Answer is Right!
Answer is Wrong!
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UPSC Geoscientist – 2023
For a simple pendulum at an angle α from the vertical, the restoring torque about the point of suspension is given by τ = -mgl sin α, where m is the mass of the bob, g is the acceleration due to gravity, l is the length of the pendulum, and α is the angular displacement. According to Newton’s second law for rotation, the torque is also equal to Iβ, where I is the moment of inertia and β is the angular acceleration. For a simple pendulum, I = ml². Thus, ml²β = -mgl sin α. This gives β = -(g/l) sin α. The magnitude of the angular acceleration is |β| = (g/l) sin α. Since g and l are constants, the angular acceleration is proportional to sin α.
– Restoring torque τ = -mgl sin α.
– Torque τ = Iβ.
– Moment of inertia of a simple pendulum I = ml².
– Angular acceleration β = τ/I = -(g/l) sin α.
– Magnitude of angular acceleration is proportional to sin α.