Friction
force that resists sliding motion between surfaces that are touching
1st Law of Motion
states that an object at rest will stay at rest and an object in motion will stay in motion unless it is acted upon by an outside force
2nd Law of Motion
an object acted on by an unbalanced force will accelerate in the direction of that force
3rd Law of Motion
for every action there is an equal an opposite reaction
static friction
friction that acts between objects that are not moving
sliding friction
friction that occurs when one solid surface slides over another
rolling friction
friction that occurs when objects are rolling over a surface
gravity
attractive forces between objects, the force that moves objects downhill
weight
measure of the force of gravity acting on an object multiplied by its mass
work
force extended on an object that causes it to move
inertia
tendency of an object to resist a change in motion
velocity
rate at which speed changes in a given direction
acceleration
objects speeds up, slows down or changes direction
force
push or pull exerted on an object
balanced forces
forces that are equal but opposite in direction- when acting on each other they cancel out and no change occurs to the object in motion
unbalanced forces
unequal forces that do not cancel when acting on an object and cause a change
speed
the distance an object travels per unit of time