JEE Main201911 Jan 2019Evening ShiftPhysicsOscillationsActual
A pendulum is executing simple harmonic motion and its maximum kinetic energy is K ₁ . If the length of the pendulum is doubled and it performs simple harmonic motion with the same amplitude as in the first case, its maximum kinetic energy is K ₂
Options
- AK₂=2 K₁
- BK ₂= K ₁ 2
- CK ₂= K ₁ 4
- DK₂=K
Correct answer
A. K₂=2 K₁
Step-by-step solution
K= 1 2 m ² x² K_ = 1 2 m ² A² A =L = g L K= 1 2 m g L L² ²= 1 2 m g L ² K₁ K₂ = L 2 L = 1 2 K₂=2 K₁ K ₁ ~K ₂ = L 2 ~L = 1 2 K ₂=2 ~K ₁