A push or a pull on objects
equal forces on an object that cancel out; no net force
unequal forces on an object; you get a net force; causes the object to accelerate
a change in position
What do you need to see motion?
a reference point
how far you go
distance between starting and ending point
how fast you go
distance divided by time
speed with a direction
What changes velocity?
speed or direction
changing velocity over time
(final velocity-original velocity) divided by time
3 Things That Affect Acceleration
speeding up, slowing down, changing direction
resistance to motion
What affects Inertia?
mass of an object; the larger the mass the greater the inertia
What's another name for the First Law of Motion?
Law of Inertia
What does the First Law of Motion say?
An object at rest or motion will stay that way unless an outside force (net force)
What does the Second Law of Motion show?
it shows how force, mass and acceleration are related
What does the Second Law of Motion say?
a net force on an object causes it to accelerate in the direction of the force
Second Law of Motion formula
mass times acceleration
What's another name for the Third Law of Motion?
What does the Third Law of Motion say?
for every action force there is an equal and opposite reaction force
resistant force caused when two surfaces touch
What affects friction?
type of surface and mass of an object; NOT the amount of surface touching
3 Types of Friction
Static, Sliding, Rolling
the greatest kind of friction; keeps the objects at rest
less than static; when objects start to move
least kind of friction; occurs with wheels and rollers
3 Ways to Decrease Friction
Lubrication, Wheels and Rollers, Sanding and Polishing
inertia in motion
What is momentum affected by?
mass and velocity
mass times velocity