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1) If the heart works 60J in one minute, what is its power?

2) Name the term used for the sum of kinetic energy and potential energy of a body.
3) In an oscillating pendulum, at what positions the potential and kinetic energies are maximum?
4) A 2m high person is holding a 25 kg trunk on his head and is standing at a roadways bus-terminal. How much work is done by the person?
5) What will cause greater change in kinetic energy of a body changing its mass or changing its velocity.


1) We will take time in seconds so it becomes 60sec. Power=work/time=60J/60sec =1W 2.) Total energy 4) 0 work done 5) changing its velocity.
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1. Power = work done/ time taken = 60J / 60s = 1 J/s = 1 W
2. Mechanical Energy or you can say total energy also.
3. Potential energy is highest at the extreme positions; where the the height of the pendulum bob is highest. Kinetic energy is maximum at the mean position of the the bob where the height of the bob is lowest.
4. Work done is 0 as the displacement of the box is 0.
5. Change in velocity will cause greater change in KE than change in mass as KE is proportional to velocity as square if velocity whereas it is related to mass linearly.
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