FORCE, ENERGY &
MOTION
SOL 4.2
SPEED describes how
fast
an object is moving.
ENERGY may exist in two states:
potential or kinetic.
Potential energy is
stored energy.
Kinetic energy is the
energy of motion.
Potential energy is stored energy.
What are some other examples of potential energy?
*A baseball pitcher right
before he throws the ball.
*A roller coaster at the top of a tall hill.
Kinetic energy is energy of motion.
What are some other examples of kinetic energy?
*A baseball pitcher as he throws the ball.
*A roller coaster going down the hill.
Kinetic energy is energy of motion.
*ALL moving objects have kinetic energy.
*When an object is in motion, it changes
position by moving in a direction:
A force is any push or pull
that causes an object to:
• Forces
transfer
energy.
•When you
throw a ball,
the force of
your arm
pushes the ball
into the air.
• Energy is
transferred
from your arm
to the ball.
Without force, an object at
rest will stay at rest!
The pull of gravity is a force that might set an object (or a skier) in motion.
The pull or push of a magnet is another force that can move objects.
The force you exert with your legs or arms can set a ball in motion.
Unless acted on by a force, an
object in motion will stay in
motion!
An object will continue to move until a force slows or stops it.
•The force stopping the object's motion might be an obvious one - the ground!
The greater the force, the
greater the change in motion.
The more massive an object,
the less effect a force will have
on an object.
For example, it's easier to push a light plastic ball than a more massive boulder.
It's also harder to stop a boulder when it is rolling down a slope.
FRICTION is the resistance to
motion created by two objects
moving against each other.
.
the sled and the snow, for instance
FRICTION creates
Rub your hands together!
The skier is standing at the top of the mountain. Is the picture
meant to show potential or kinetic energy?
Which object on the shelf has the
greatest potential energy?
the red vase on the second shelf
the blue vase on the top shelf
the white box on the bottom shelf
These passenger are just starting their descent. What's
happening?
potential energy is changing to kinetic energy