Transcript 05.31.2011_5.6.1 and 5.4.1.docx.d2

APPLIED POTENTIAL
AND KINETIC ENERGY
Mr. Smet’s
Scientific
Studies
DO NOW
1. Place your homework on the table in
front of you.
2. Answer the following:
What is the law of conservation of
energy?
Explain how a roller coaster works using
the Law of Conservation of Energy.
AGENDA
1. Do Now
2. Introduction
3. Homework Review
4. Calculations
5. Calculation W.S.
6. W.S. part 2
7. Exit Slip
8. Closing
OBJECTIVES:
5.6.1 SWBAT define the Law of
Conservation of Energy.
5.4.1 SWBAT explain how
potential and kinetic energies are
related using the conservation of
energy.
AGENDA
1. Do Now
2. Introduction
3. Homework Review
4. Calculations
5. Calculation W.S.
6. W.S. part 2
7. Exit Slip
8. Closing
QUESTION 1
 At which point does a train on this roller coaster:
 Have the most gravitational potential energy? Explain your
choice.
 have the most kinetic energy? Explain your choice.
 Have both kinetic and gravitational potential energy? Explain
your choice.
 a. The train has the most potential energy at Point B
because it is the highest point on the track.
 b. The train has the most kinetic energy at Point G
because it has converted the most energy (PE from
Point B) into kinetic from the first hill.
 c. The train has both kinetic energy and potential
energy at points D, E and F because it has both
height (PE) and speed (KE) at those points.
QUESTION 2
Kinetic energy is related to the
speed of an object. In which place,
Point E or Point F, is the train
moving faster? Explain in terms of
kinetic energy.
QUESTION 2 ANSWER
The train is moving faster at
point E because it has more
kinetic energy there. When the
train climbs the hill to point F,
it has less kinetic energy and
less speed.
QUESTION 3
As the train travels on the track,
the energy of the train changes
back and forth from gravitational
potential to kinetic. What other
energy transformations occur as
the train travels the track?
Explain.
QUESTION 3 ANSWER
Some of the kinetic energy is
turned into thermal energy and
sound due to the friction between
the train and the tracks. Friction
between the air and the train also
transforms some kinetic energy
into wind and thermal energy.
QUESTION 4
Why can’t a roller coaster
go up a hill that is higher
than the hill it just came
down?
QUESTION 4 ANSWER
Because in order to climb a bigger hill, energy
must be added to the train. The role-play
pointed out that a roller coaster is at its
maximum energy at the first hill. After that, no
energy is put into the system and some energy
is lost by heating and sound as the roller
coaster travels. So there is less energy
available to transform from kinetic to potential
for each subsequent hill.
AGENDA
1. Do Now
2. Introduction
3. Homework Review
4. Calculations
5. Calculation W.S.
6. W.S. part 2
7. Exit Slip
8. Closing
CONCEPT
Last week, we learned about the
Conservation of Energy.
CONCEPT
Last week, we learned about the
Conservation of Energy.
Energy cannot be lost or destroyed.
TOTAL ENERGY
Total energy is the amount of energy
an object has.
TOTAL ENERGY
Total energy (TE) is the amount of
energy an object has.
 Total Energy = Potential Energy + Kinetic Energy
TE
= PE
+ KE
EXAMPLE:
CFU
A.
PE = 7J
KE = 6J
B.
PE = 12 J
KE = 8 J
B.
PE = 32 J
KE = 49 J
DETERMINING PE OR KE
If you know both Total Energy and
Potential Energy/Kinetic Energy, you
can find the other.
KE = TE – PE
PE = TE - KE
CFU
A.
PE = 17J
KE = 6 J
TE = ?
B.
PE = 15 J
KE = ?
B.
PE = ?
KE = 20 J
CFU
A.
PE = 6J
KE = 12 J
TE = ?
B.
PE = 11 J
KE = ?
B.
PE = ?
KE = 15 J
AGENDA
1. Do Now
2. Introduction
3. Homework Review
4. Calculations
5. Calculation W.S.
6. W.S. part 2
7. Exit Slip
8. Closing