1. Potential and Kinetic Energy: Energy in the Pole Vault
Chapter 2, Section 8
Potential and Kinetic Energy: Energy in the Pole Vault

2. November 1, 2010 HW: 2.8 PTG #1, 2, 3, 6, 7, 8, 13, Due Friday
Learning Objectives:
Describe kinetic, gravitational potential, and elastic energy and the variables that influence them
Explain conservation of energy
Success Criteria:
Apply equations for kinetic energy, gravitational potential energy, and elastic energy
Recognize that restoring forces are active when objects are deformed
Apply the equation for the force necessary to compress or stretch a string
Conduct simulations of transformations of energy involved in the pole vault.
Do Now:
Write LO and SC in notebook
WDYS/WDYT
pg 220
Agenda:
Do Now
LO/SC

3. Investigate #1-9
Worksheet

4. 2.8 Physics Talk What is happening to speed at each position?
Force gives the ball an upward speed
Speed decreases as the ball is acted upon by gravity
Vertical position is maximum, but vertical speed is 0
Ball increases in speed as it is acted upon by gravity 3 2 4 1

5. 2.8 Physics Talk What changed in terms of energy?
Total energy is always the same, it is just transformed from one form to another

6. 2.8 Physics Talk What is Kinetic Energy (KE)
What is Gravitational Potential Energy?
Energy associated with motion
The energy an object possesses because of its vertical position from Earth

7. 2.8 Physics Talk What is potential energy?
What is the Law of Conservation of Energy?
Energy associated with position
Energy cannot be created or destroyed! It can be transformed from one form to another but the total energy remains constant!

8. 2.8 Physics Talk What changed in terms of energy?
Ball has only kinetic energy
Kinetic energy decreases, Gravitational Potential Energy increases
Kinetic Energy=0, Max GPE
GPE decreases, Kinetic Energy increases 3 2 4 1

9. 2.8 Physics Talk
What energy is needed to get the ball moving? To get it to stop?
What is the equation for Work?
WORK!
Work is the force applied over a distance
Causes the change in forms of energy
Work=Force x Distance
W=Fd W F d

10. Think about launching the penny…
Work was done on the ruler to add energy to the system
After bending the ruler it had Elastic Potential Energy
When you released the ruler it applied a force over a distance to the penny (work)
The penny now has Kinetic Energy
As it travelled up, the KE became GPE
At the peak, the penny had no KE and all GPE
As the coin fell GPE became KE
Sum of the GPE and KE was always the same (conservation of energy)

11. Pole Vaulting!!!
Food energy provides muscular energy to run which is KE
Vaulter’s KE is converted to Elastic PE in the pole
As the pole unbends, EPE is transferred to the vaulter as GPE
As vaulter falls GPE is transferred to KE
Total energy remains the same!

12. Equations!!! Work Elastic (spring)PE W=Fd EPE=1/2kx2 F=force (N)
d=distance (m)
W=work (Joules J)
EPE=1/2kx2
K=spring constant (N/m)
x=amount of bend in meters
EPE=Joules (J)

13. Equations!!! Gravitational Potential Energy Kinetic Energy GPE=mgh
GPE=Joules (J)
m=mass (kg)
g=gravity (m/s2)
h-=height (m)
KE=1/2mv2
KE=Joules (J)
v=speed (m/s)

14. Practice Problems Pg. 226-227 #1-Whole group #2-Whole Group
#3-Small Group
#4-Individually

15. Vocab Activity Book Definition Definition in your words
2.8 Vocab Boxes.docx
Example or Equation
Picture/Drawing

16. Practice Problems
Work and Energy Practice Problems.pdf

17. Relay
Energy Relay.pdf
Work and Energy Relay.pdf