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Forces and Motion

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displacement
the direction and the distance between the final position and the starting position
speed
the distance traveled divided by the time needed to travel that distance ( s = d/t )
velocity
the speed in a particular direction
acceleration
a change in velocity divided by the amount of time over which the change occurs ( a = F/m )
force
a push or a pull ( F = ma )
inertia
measures an object's tendency to resist a change in motion
balanced forces
forces that cancel eachother out ( they do not cause a change in motion )
unbalanced forces
forces that are not balanced; they do cause a change in motion ( the object will move in the direction of the stronger force )
friction
resists motion between two touching surfaces
gravity
a pull that all matter exerts on other matter
centrifugal force
causes the object to move away from the center
centripetal force
causes the object to move in a circular path towards the center
Newton's First Law of Motion
an object at rest tends to stay at rest, an an object in motion keeps moving in a straight line at constant speed until an outside force ( or unbalanced force ) stops it
Newton's Second Law of Motion
acceleration depends on the mass of an object and the force pushing or pulling the object
Newton's Third Law of Motion
for every action, there is an equal and opposite reaction that happens at the same time
Newton's First Law of Motion example
If a ball is not moving, it will stay that way until some force makes make it move.
Newton's Second Law of Motion example
If two bike riders pedal with the same force, the rider moving less mass accelerates fatser.
Newton's Third Law of Motion example
A girl jumps on a trampoline. The action is the girl pushing down on the trampoline. The reaction is the trampoline pushing up on her.
balanced force example
A boy is pushing up against a cement wall. No matter how hard he tries, the wall will not move.
unbalanced force example
A towtruck towes a car after a wreck. As a result, the car is moving in the direction of the towtruck.
centrifugal force example
A person rides the merry-go-round.
centripetal force example
The moon orbits Earth.
velocity example
A car is traveling 30 mph/south.
speed example
The long distance jogger's time was 6 mph for the race.
acceleration example
A softball is hit into the outfield.
acceleration formula
a= F/m or fV - iV/t
force formula
F = ma
mass formula
m= F/a