Question

The diagram below shows a pendulum which was released from position A.

(a) What form(s) of energy did the pendulum have at

A?

B?

C?

(b) Eventually the pendulum would stop moving. Explain what has happened to the initial energy of the pendulum.

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Answer 1

Answer:

(a)

A-potential energy

B-potential energy increase and kinetic energy decrease

C-kinetic energy

(b) when there is no force given to the pendulum, obviously the pendulum will stop moving

Answer 2

The answers are as follows:

(a) The pendulum had the following forms(s) of energy at the given positions:

• At A, the pendulum is at its extreme. The potential energy at this point is maximum. It has no kinetic energy.
• At B, the pendulum has both potential and kinetic energies.
• At C, the pendulum is at its mean position. The kinetic energy at this point is maximum. It has no potential energy.

(b) The pendulum will eventually stop moving because of damping. The air resistance (air friction) causes the initial energy to dissipate as heat energy.