1. Energy
Ch. 4-1

2. Distinguish between kinetic and potential energy.
Objectives
Distinguish between kinetic and potential energy.
Explain different forms of potential energy.
CLE Investigate the Law of Conservation of Energy.

4. Energy (E) is the ability to cause change. Energy comes in many forms.
The Nature of Energy
Energy (E) is the ability to cause change.
Energy comes in many forms.
Energy plays a role in every activity you do.

5. B. What is Kinetic Energy?
Kinetic Energy (KE) – energy in the form of motion
The amount of KE depends on mass and velocity.
80 km/h
50 km/h
Which has the most KE?
Which has the least KE?
80 km/h truck
50 km/h motorcycle

6. Joule – the SI unit used to measure energy ( J )
3. Equation
KE = ½ mass x velocity2
Joule – the SI unit used to measure energy ( J )

7. C. What is Potential Energy?
Potential Energy (PE) - stored energy in a motionless object.
Gravitational potential energy– (GPE) stored by things that are above the Earth’s surface.
Anything that can fall has GPE!

8. Gravitational Potential Energy
The Nature of Energy
Gravitational Potential Energy
Even motionless objects can have energy. This energy is stored in the object.
A hanging apple in a tree has stored energy (GPE) due to its height above ground.

9. D. Gravitational Potential Energy
The amount of GPE an object has depends on its mass, the acceleration due to gravity (9.8m/s2), and its height above ground.

10. Changing GPE? Which boulder has greater gravitational PE?
What other ways can an object store energy?

11. Changing GPE
The GPE of an object can be increased by increasing its height above the ground.
2. If two objects are at the same height, then the object with the larger mass has more gravitational potential energy.

12. 3. GPE = mass in kilograms x 9.8 m/s2 x height in meters.

13. E. Changing Energy Type
As the roller coaster descends from the highest point, its potential energy changes to kinetic energy

14. Roller Coaster Diagram

15. KE to GPE

17. F. Types of Potential Energy
1. Elastic potential energy – Energy stored by things that stretch or compress.
Ex. A stretched rubber band, springs

18. Types of Potential Energy
2. Chemical PE – energy stored in chemical bonds between atoms.
Ex – Gasoline, Food

19. How does food provide energy for your body?
Chemical potential energy is stored in the chemical bonds between atoms in the food. When you digest food, your body breaks the molecules in the food down, breaking the chemical bonds and releasing energy.

20. Question 2 Energy is the ability to cause __________. A. change
B. heat
C. motion
D. work

21. Answer
The answer is A. Energy is the ability to cause change and has several different forms.

22. Question 3 The kinetic energy of an object depends on __________.
A. the object’s mass and speed
B. the object’s mass
C. the object’s speed
D. the acceleration of the object

23. Answer
The answer is A. Kinetic energy depends on both the mass and speed of the moving object.

24. Is energy lost when a car burns gasoline? Explain.
No, energy is always conserved. When a car burns gasoline, that energy is changed to kinetic energy which makes the car move. In turn, friction from the tires on the road converts some of that kinetic energy into thermal energy, which remains in the road and the tires.

25. CLE 3202.2.6 Investigate the Law of Conservation of Energy.
Objective: Distinguish between kinetic and potential energy.
Objective: Explain forms of potential energy.

26. Distinguish between kinetic and potential energy.
Objectives
Distinguish between kinetic and potential energy.
Explain different forms of potential energy.
CLE Investigate the Law of Conservation of Energy.