The document discusses different types of energy: - Work is done when a force causes an object to move, and is calculated as work (W) equals force (F) multiplied by distance (d). - Kinetic energy is the energy of motion and is calculated as kinetic energy (KE) equals one-half mass (m) multiplied by velocity (v) squared. - Potential energy is stored energy due to an object's position or state, such as height, and is calculated as potential energy (PE) equals mass (m) multiplied by gravity (g) multiplied by height (h).

1. Work &
ENERGY

2. Energy
• The ability to do work
Work
• Using energy to exert a force to
move an object

3. Work = Energy
&
Energy = Work
• The work done is equal to the energy
used to do the work.

4. Calculating Work:
W = 0, if F = 0
W = F d
W = 0, if d = 0
No work done if object
doesn’t move.
No work done, whenever
there is no force.
Unit: Joule (J) is a Nm

5. A person pushes with a 110 N force
for a distance of 30 m. How much
work was done?
Examples:
W = F d
W = ( 110 N ) ( 30 m )
W = 3300 N m
or
W = 3300 J 1 Joule (J) = 1 N m

6. Potential and
Kinetic Energy

7. Kinetic Energy:
Energy in Motion
Calculating KE:
KE = ½ m v2

8. KE = 72 J
Example:
What is the KE of 100 kg of
water moving at 1.2 m/sec?
KE = 72 ( kg m )/s
22
KE = mv
2
2
1
KE = ( 100 kg ) ( 1.2 m/s )
2
2
1
KE = ( 100 kg ) ( 1.44 m /s )
22
2
1

9. KE = mvKinetic Energy Fact:
2
2
1
The kinetic energy increases dramatically with increasing speed.
35 mi/hr
4 x speed
16 x energy
140 mi/hr70 mi/hr
2 x speed
4 x energy

10. What is Potential Energy?
oEnergy that is stored
and waiting to be
used later

11. What is Potential Energy?
o Potential energy is
stored energy
o P.E. = mass x gravity x height
o P.E. = mghDon’t look down,
Rover!
Good boy!

12. Law of Conservation of Energy
• Energy cannot be created or destroyed
• Energy can be transferred from one type or
state to another