Physics
Which of the following is not an example of conservation of mechanical energy :
- free fall
- ideal pendulum
- block sliding down a rough surface
- satellite orbiting the earth
Work, Energy & Power
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Answer
block sliding down a rough surface
Reason — Mechanical energy is conserved when only conservative forces act. In free fall, an ideal pendulum and a satellite orbiting the earth, kinetic and potential energy change into each other while total mechanical energy remains constant. However, when a block slides down a rough surface, friction converts some mechanical energy into heat, so mechanical energy is not conserved.
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