2. What is Energy?
Energy – the ability to do work or cause
change.
when an object does work on another object, some
of the energy is transferred to that object.
Energy is measured in Joules
Joule – a unit of measure equal to one newton-meter
3. What is work?
Work – force exerted on an object that causes it
to move
Example: pushing a shopping cart
4. Two Types of Energy
Kinetic Energy – energy in motion
Potential Energy – stored energy
5. Kinetic Energy
The more work you do on an object, the more
energy you give the object.
The greater the mass of a moving object, the
more kinetic energy it has. (Ex. a bowling ball
has more kinetic energy than a golf ball traveling
at the same velocity)
Kinetic energy increases as velocity increases.
6. Calculating Kinetic Energy
Kinetic Energy = Mass x Velocity2
2
Ex. – What is the kinetic energy of a 10kg wagon
moving at 5 m/s?
kinetic energy = 10 x 52 = 10 x 25 = 250
2 2 2
kinetic energy = 125 Joules
7. Potential Energy
Energy that is held in readiness and therefore
has potential to do work.
Ex. A spring compressed in a wind-up toy
Elastic potential energy – energy stored in a
stretched or compressed object (rubber band)
8. Potential Energy
Gravitational potential energy (GPE)–
potential energy that depends on height; an
object lifted.
Gravitational potential energy = weight x height
Ex. What is the GPE of a rock that weighs 600 newtons
positioned 20 meters of the ground?
GPE = 600 x 20
GPE = 12,000 Joules
