How can you use a simple model to describe a wave and its features?

What are similarities and differences between refraction, reflection, diffraction and absorption?

Suppose a comet has an orbital period of 309.1 years around the sun. what is it’s average distance from the sun?

Greg drew a diagram to compare two of the fundamental forces. which labels belong in the areas marked x, y and z? gravitational force electromagnetic force x. attractive y repulsive z: infinite range x: infinite range y attractive z. repulsive x. always attractive y: infinite range z: attractive or repulsive x. attractive or repulsive y infinite range z: always attractive