What is energy?

Energy- the ability to do work

The unit for energy is Joule (J)– just like work.

Kinetic Energy- energy in motion

All moving objects have kinetic energy

Kinetic Energy = KE = mv2

2

2

2mvKE

What is the kinetic energy of a car that has a mass of 1,200 Kg and is moving at a speed of 20 m/s?

KE= 1,200 x 20 x 20 ÷ 2 = _____________

What is the kinetic energy of a car that has a mass of 2,400 kg and is moving at 20 m/s? How does this kinetic energy of the car in the above example compare?

KE= 2,400 x 20 x 20 ÷ 2 = _____________

Potential Energy- The energy that an object has because of the position, shape, or condition of the object

Gravitational Potential Energy - energy stored as a result of position or height.

▪ GPE = weight x height

What is the gravitational potential energy of a book with a weight of 13 N at a height of 1.5 m off the ground?

GPE= 13 x 1.5 = _________________

What is the gravitational potential energy of a cat that weighs 40 N standing on a table that is 0.8 m above the ground?

GPE = 40 x 0.8 = ___________________

What is the gravitational potential energy of a diver that weights 500 N standing on a platform that is 10 m above the ground?

GPE = 500 x 10 = _____________________

Mechanical Energy- the total energy of motion and position of an object.

Mechanical Energy (ME) = potential energy + kinetic energy (J) (J) (J)

What is the mechanical energy of a book being held in the air that has 100 J or potential energy and 50 J of kinetic energy?

100 + 50 = __________________

What is the mechanical energy of a goose standing on a rock that has 75 J of potential energy and 60 J of kinetic energy?

75 + 60 = _______________

Thermal Energy- is all of the kinetic energy due to motion of the particles

Chemical Energy-The energy in a compound that changes as its atoms are rearranged

Electrical Energy- is the energy of moving electrons.

Sound Energy- is caused by an object’s vibrations.

Light Energy- Produced by the vibrations of electrically charged particles.

Nuclear Energy- The energy that comes from the nucleus of an atom

Friction-A force that opposes motion between two surfaces that are touching

Energy cannot be created or destroyed.

Energy changes forms.