1. Explain what each variable in Newton's Law of Gravitational Attraction means. Further, describe how this equation explains the differences between the sun and the moon's contribution to tide-generating forces.
2. Describe what happens to a deep-water wave as it approaches a beach and enters shallow water. How does it change? What conditions would have to be met for the wave to break?
3. Define what wave refraction is and explain how it occurs. How might wave refraction impact sand movement on a beach?