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A pendulum executing simple harmonic motion has maximum kinetic energy K₁. If the length of the pendulum is doubled and it oscillates with the same amplitude, its maximum kinetic energy is K₂. Then

Asked in JEE Main 11th Jan 2nd Shift 2019 · Time period, length and g

Answer: (2) K₂=(K₁)/2

Step-by-step solution

Kₘₐₓ=1/2 m vₘₐₓ²=1/2 m A²ω², and for a pendulum ω²=g/L.

So Kₘₐₓ=(mgA²)/(2L)∝1/L at fixed amplitude, and doubling L gives K₂=(K₁)/2.

Why the other options are wrong

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