As the pendulum moves from point 1 to point 3, what happens to its mechanical energy? A. Potential energy is converted to kinetic energy and back again. B. Kinetic energy is converted to potential energy only once. C. Potential energy is converted to kinetic energy only once. D. Kinetic energy is converted to potential energy and back again.Reset Submit

The correct answer is A. Potential energy is converted to kinetic energy and back again.

Here's the step-by-step explanation:

1. At point 1, the pendulum is at its highest point in the swing, so it has maximum potential energy and minimum kinetic energy.

2. As the pendulum swings down towards point 2 (the lowest point), potential energy is converted into kinetic energy. The pendulum speeds up and its kinetic energy increases while its potential energy decreases.

3. At point 2, the pendulum has maximum kinetic energy and minimum potential energy.

4. As the pendulum swings up towards point 3, kinetic energy is converted back into potential energy. The pendulum slows down, so its kinetic energy decreases while its potential energy increases.

5. At point 3, the pendulum is again at a high point in the swing, so it has maximum potential energy and minimum kinetic energy, just like at point 1.

So, throughout the swing from point 1 to point 3, potential energy is converted to kinetic energy and back again.