| A | B |
|---|
| a push or a pull | force |
| reduces friction | wheels |
| oil | reduces friction |
| balanced forces | opposite and equal |
| force equals | mass times acceleration |
| speed or direction does not change when | forces are balanced |
| motion must change when | forces are unbalanced |
| the force of friction always | opposes the motion of objects |
| for every action, there is an equal | and opposite reaction |
| when speed or direction change, the force present present must be | unbalanced |
| Newton's 2'nd law | unbalanced force |
| Newton's 3'rd law | forces act in pairs |
| the attractive force between masses | gravity |
| terminal velocity | body stops accelerating |
| newtons | a measurement of weight |
| weight varies with | gravity |
| orbital projectile motion | forward inertia balances gravity |
| keeping an object doing what it is already doing | requires no force |
| sliding friction depends on | weight and kind of surface |
| resistance to change in motion | inertia |
