TOPIC: EnergyAIM: How can energy be different?

2 TypesOf Energy

1. Kinetic Energy energy of motion

Kinetic Energy facts:

The faster/greater the velocity of an object the greater the Kinetic energy of the object in motion

The larger/greater the mass of an object the greater the Kinetic energy the object in motion

2

Examplem= 2 kgv= 2m/s KE = ?

KE = mv2

2

KE = 2 x 22

2KE = 2 x 4 2KE = 4 J

Examplem= 10kgv= 3m/s KE = ?

KE = mv2

2

KE = 10 x 32

2KE = 10 x 9 2KE = 45 J

Examplem= 5kgv= 1m/s

KE = ?

KE = mv2

2

KE = 5 x 12

2KE = 5 x 1 2KE = 2.5 J

2.Potential Energy stored energy that is not moving/ not working

Examples:1. Stretched rubber band posseses a lot of Potential Energy

When you let the rubber band go the PE is released

2. Unlit match the PE is stored until the match is lit

The massive ball of a demolition machine and the stretched bow

possess stored energy of position = Potential Energy

REVIEW:

KINETIC OR

POTENTIAL ENRGY?

GravitationalPotential Energy

The potential energy that depends on height

The greater the weight of the object the greater the Grav. Pot. Ener. will be

The greater the height of the object the greater the Grav. Pot. Ener. will be

Example: Person on a 3m high diving

board has more GPE than person on 1m high board

GPE = weight x heightExample:What is the GPE of a 780 N diver on a diving board that is 10 m high?

•GPE = w x h•GPE = 780N x 10m•GPE = 7800 J

Example:What is the GPE of a 320 N diver on

a diving board that is 5 m high?

GPE = w x h

GPE = 320N x 5m

GPE = 1600 J

Example:Who has a higher GPE?

A) 300N diver on a 3m diving board

B) 75N painter on an 8m ladder

C) 500N diver on a 2m diving board

Date # Assignment

Mon 11/30 9 Textbook page 133 # 1,2,3,5,6,7

Tues 12/1 10 Textbook page 493 # 1,2,3,5

Wed 12/2 11 Textbook page 500 # 3,4 page 506 # 2

Thurs 12/3

TEST

Fri 12/4

Do Now:If a 70N squirrel is on a branch that is 4 meters above the ground, what is the gravitational potential energy? Show all work!!!

TOPIC: EnergyAIM: How does energy change from one type to another?

EnergyConversion

•Change of energy from 1 type to another

•KE PE •PE KE

Example: Throwing a ball into the air

V = 0 m/s

PE KE V

V

KE PE

V = 0 m/s

V PE KE

PE = maxKE = 0 J

PE = maxKE = 0J

KE = 0 J

KE = max

PE = max PE =

max

PE = 0 J

Speeding upSlowing

down

V = 0m/s

V = 0m/s

V = max

KE = 0 JPE KE KE PE

As the car loses height, it gains speed. PE is changed into KE. The sum of the KE and PE is constant. It never changes.

On the platform:

PE = maxKE = 0 Joules

During the jump:KE is increasingPE is decreasing

In the water:KE = 0 JoulesPE = max

http://www.youtube.com/watch?v=vl4g7T5gw1M

PE KE