Question

Illustrate the law of conservation of energy by discussing the energy changes which occur when we draw a pendulum bob to one side and allow it to oscillate. why does the bob eventually come to rest ? what happens to its energy eventually? Is it a violation of the law of conservation of energy? This question is very short

Answer 1

It is because of gravitational force which opposes the oscillatory motion. Here Kinetic energy changes to some other form of energy.Energy did not destroyed or created .

Answer 2

Answer♡

The law of conservation of energy states that energy can be neither created nor destroyed. It can only be converted from one to another.

Consider the case of an oscillating pendulum.

• When a pendulum moves from its mean position P to either of it extreme positions A or B, it rises through a height h above the main level P. At this point, the kinetic energy of the bob changes completely into potential energy. The kinetic energy becomes zero, and the bob possesses only potential energy. As it moves towards P, its potential energy decreases progressively. Accordingly, the kinetic energy increases. As the bob reaches a point P, its potential energy becomes zero and the bob processes only kinetic energy. This process is repeated as long as the pendulum oscillates. the bob does not oscillate forever. It come to rest because air resists its motion. The pendulum loses its kinetic energy to overcome this friction and stops after sometime.

• The law of conservation of energy is not violated because the energy lost by the pendulum to overcome friction is gained by its surroundings. Hence, the total energy of the pendulum and the surrounding system remain conserved.

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