Chapter 5Section 1: What is Energy?

Energy

Energy is the ability to do work

Work is done when a force makes an object move or

change its direction.

Example

When you kick a soccer ball, you are doing work on the ball and then the

ball does work on the goal.

When one object does work on another, energy is

transferred.

Energy is expressed in the units Joules (J)

Kinetic Energy

Kinetic energy is the energy of motion

Kinetic energy is the energy of motion

All moving objects have kinetic energy.

Kinetic energy depends on mass and speed

Kinetic energy= mv2/2M=mass

V2=velocity2

To increase kinetic energy, increase the mass(m) or speed(v) of the object.

Potential Energy

Potential energy is the energy an object has

because of its position

There is more potential energy in a car on top of a

hill than a car on a flat street.

Gravitational potential energy is a transfer of energy to an object by

lifting it in the air.

Example

Holding a ball over your head vs it resting on the

ground.

To calculate gravitational potential energy:

Gravitational potential energy=

weight x height

Weight is the amount of force needed to lift an object and height is a

distance

Mechanical Energy

Mechanical Energy is the total energy of motion and

position of an object

Mechanical energy=potential energy+kinetic energy

Other forms of energy

• Thermal Energy• Chemical Energy• Electrical Energy• Sound Energy• Light Energy• Nuclear Energy