What does Coulomb's law applies to: 1. Like charges and unlike charges
2. Charge motion
3. gravitational fields
4. moving objects

The percent efficiency of a machine can never be 100% (or greater), because in the real world some energy is always converted into a. heat b. work c. input force d. output force

Explain earth's motion, using the terms "precession" and "rotation" in your answer.

What sort of waves exhibit the doppler effect?