**Mass and Energy**

- kinetic energy
- two kinds of potential energy are electrical and chemical
- radioactive energy of light distributed by photons

Speed, velocity, acceleration, and Newton’s laws of movement

Universal law of gravitation, with force diminishing with a square distance

Second Newton’s law: force is equal mass x acceleration. Gravity constant *g* = 9.81 m/s2 = 32.2 ft/s2

Gravitation is a force of attraction exerted by each particle or matter on other matter.

Gravity is a force that attracts a body toward the center of earth.