Chapter 2, Section 8

Potential and Kinetic Energy: Energy in the Pole Vault

November 1, 2010HW: 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– Investigate

Investigate #1-9• Worksheet from

Mattea

November 2, 2010HW: 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: – Thinking about pole

vaulting…• What did the ruler

represent?• The ball?• The penny?

• Agenda:– Do Now– LO/SC– Investigate(Finish)– Physics Talk

2.8 Physics Talk• What is happening

to speed at each position?

1. Force gives the ball an upward speed

2. Speed decreases as the ball is acted upon by gravity

3. Vertical position is maximum, but vertical speed is 0

4. Ball increases in speed as it is acted upon by gravity

1

4

3

2

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

2.8 Physics Talk• What is Kinetic

Energy (KE)?

• What is Gravitational Potential Energy (GPE)?

• Energy associated with motion

• The energy an object possesses because of its vertical position from Earth

2.8 Physics Talk• What is potential

energy (PE)?

• What is the Law of Conservation of Energy?

• Energy associated with position (stored)

• Energy cannot be created or destroyed! It can be transformed from one form to another but the total energy remains constant!

2.8 Physics Talk• What changed in

terms of energy?1. Ball has only

kinetic energy

2. Kinetic energy decreases, Gravitational Potential Energy increases

3. Kinetic Energy=0, Max GPE

4. GPE decreases, Kinetic Energy increases1

4

3

2

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• Units=Joules J

W

dF

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)

November 3, 2010HW: 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: – Explain what

happens to KE and PE as you ride your bike up a hill.

• Agenda:– Do Now– LO/SC– Vocab Activity

Pole Vaulting!!!• http://www.youtube.com/watch?v=kJu

citWzywM&feature=fvw• 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!

Equations!!!• Work

• Elastic (spring)PE

• W=FdF=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)

Equations!!!• Gravitational

Potential Energy

• Kinetic Energy

• GPE=mghGPE=Joules (J)

m=mass (kg)

g=gravity (m/s2)

h-=height (m)

• KE=1/2mv2

KE=Joules (J)

m=mass (kg)

v=speed (m/s)

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

Vocab ActivityBook Definition Definition in your words

2.8 Vocab Boxes.docx

Example or Equation Picture/Drawing

November 4, 2010HW: 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: – Find the equations

for EPE, KE, W, etc.

• Agenda:– Do Now– LO/SC– Practice Problems

Practice Problems• W

ork and Energy Practice Problems.pdf

November 5, 2010HW: None

• 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: – Get out 2.8 HW

• Agenda:– Do Now– LO/SC– Review HW– Relay!

Relay• Energy Relay.pdf• Work and Energy Relay.pdf