The diagram shows a swinging pendulum.



Which best explains what happens to the motion of the pendulum?

AThe mechanical energy transforms to thermal energy as the pendulum slows and eventually stops moving.

BThe mechanical energy disappears as the pendulum slows and eventually stops moving.

CThe pendulum will continue moving at the same speed until someone stops it because energy cannot be destroyed.

DThe pendulum will slow down but will never stop moving because energy cannot be destroyed.

Verified Answer :

The correct answer is

A. The mechanical energy transforms to thermal energy as the pendulum slows and eventually stops moving.

In fact, we must keep in mind the presence of the air, which causes some resistance to the motion of the pendulum. As the pendulum moves through the air, part of its mechanical energy is transferred to the molecules of air because of the friction of this molecules with the surface of the pendulum. As a result, the pendulum slows down, and eventually stops. The initial energy of the pendulum has been converted into thermal energy of the molecules of air, which move faster now.

Answer:

The guy above is correct it's A