9.4 Energy
1.What is energy?
Energy simply is the ability
to do work
2. Units of
Energy
Joules (J) , just like work
Joules
Joules Joules
Joules
Joules
Joules
Joules
Joules
Joules
Joules
Joules
Joules
Joules Joules
Joules
3. Gravitational
Potential Energy
Formula
PE = mass x gravity x height
PE = m g h
4. What is
Mechanical energy that results
Gravitational from an objects position (height)
Potential
Mass = 40 kg
Energy?
Height = 2
0 meters
1
g = 9.8m/s2
PE = 784
0 Joules
392
Joules
2 meters
40
kg
1 meter
5. Kinetic
Energy Formula
KE = ½ mass x velocity
2
KE = ½ mv
2
6.What is
Kinetic Energy?
Mechanical energy that is
derived from an objects
motion (it’s moving)
Kinetic Energy?
NO
YES
Car Mass = 1000 kg
Car Velocity = 840 m/s
Kinetic Energy = 32000
0 Joules
8000
Joules
Joules
7.Other types
of Energy
Molecular, chemical, heat
sunlight, electricity, sound
Glen Canyon Dam
Hydroelectric Power Station, Arizona
Glen Canyon Dam
Hydroelectric Power Station, Arizona
How it works…
Understanding Assessment:
In your notebook, sketch a
catapult slinging an object:
-Identify the point of greatest POTENTIAL
energy of the projected object.
-Identify the point of greatest KINETIC energy
of the projected object.