A physics teacher is reheating her leftover pizza lunch in the very old teacher breakroom microwave. The microwave is so old that it doesn't even turn the food as it cooks. When the teacher takes her food out and eats it, she discovers that parts of the pizza are scalding hot, while other parts are still very cold. She explains to the students that a microwave works by producing standing waves that result in heating. She asks the students to explain why some parts of the pizza are hot while others are still cold. Below are their responses:

At the antinodes of a standing wave, the wave is shaking very rapidly, causing those parts of the pizza to get hot. At the nodes, the wave is not shaking much at all, causing those parts of the pizza to stay cold."

Explanation:

antinodes vibrate and are the opposite of nodes which are stationary.

the motion of a pendulum is a classic example of mechanical energy conservation. a pendulum consists of a mass (known as a bob ) attached by a string to a pivot point. as the pendulum moves it sweeps out a circular arc, moving back and forth in a periodic fashion.