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. *When an object is in motion, it changes position by moving in a direction: ALL *ALL moving objects have kinetic energy.

force 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! The force stopping the object's motion might be an obvious one - the ground! An object will continue to move until a force slows or stops it.

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. FRICTION creates. Rub your hands together! the sled and the snow, for instance

The skier is standing at the top of the mountain. Is the picture meant to show potential or kinetic energy?

the red vase on the second shelf the blue vase on the top shelf the white box on the bottom shelf Which object on the shelf has the greatest potential energy?

These passenger are just starting their descent. What's happening? potential energy is changing to kinetic energy