| A | B |
|---|
| acceleration | any change in velocity |
| negative acceleration | slow down |
| free fall | falling without air, the object continues to speed up until it hits the ground |
| friction | any surface force that goes against motion |
| directly proportional | when one variable changes, the other changes the same direction |
| inversely proportional | when one variable changes, the other changes the opposite direction |
| kilogram | metric unit for mass |
| mass | total number of particles/atoms in an object |
| terminal velocity | the fastest an object can fall in air |
| volume | the space an object takes up |
| weight | gravity's pull on an object |
| Newton | metric unit for force |
| gravity | 9.8 meters/second/second (or 10) |
| falling in air | as an object speeds up, it hits more air and will eventually reach its fastest speed |
| positive acceleration | speed up |
| air resistance | a type of friction caused by moving through air |
| second | unit for time |
| meters/second | unit for speed or velocity |
| meters/second squared | unit for acceleration |
