Lesson Plan:
Lesson title : Conservation of Energy
Objectives:
Identify situation in which conservation of
mechanical energy in valid.
Recognize the forms that conserved energy
can take.
Vocabulary:
work
displacement.
Direction.
Lesson Plan:
Competency :Team work
Value : Respect.
 Name
three types of energy, and write
what will happen if each of these
energies disappear ?
 Let’s
watch this video about different
types of energy

https://www.youtube.com/watch?v=Q0LBegPWzrg
 The
ability to do work.
 kinetic
energy is energy associated with
motion.

What are the SI units for KE?
• kg•m2/s2 or N•m or J
A
6.00 kg cat runs after a mouse at 10.0
m/s. What is the cat’s kinetic energy?
• Answer: 3.00 x 102 J or 300 J
 Suppose
the above cat (6.0 kg)
accelerated to a speed of 12.0 m/s. what
is the new kinetic energy ?
 Ans:432 J.
 Calculate
the speed of an 4.0*10^5 kg
airliner with a kinetic energy of 8*10^9 J
 Ans: 2*10^2
m/s
 What
is the speed of a 1.2 kg ball if its
kinetic energy is 240 J.
 Ans: 20
m/s
 One
of the world’s fastest helicopters, the
westland lynx, has a top speed of 4*10^2
km/h. if its kinetic at this is 2.0*10^7 J,
what is the helicopter’s mass?
 Ans: 3240
kg.
• the energy stored by something because of
its position .
 Some
types of PE are listed below.
• Gravitational
• Elastic
• Electromagnetic
 https://www.youtube.com/watch?v=eBsU
9DVa7ws
 Answer
the questions of the polling, sent
to you via webex 

What are the SI units?
• kg•m2/s2 or N•m or J

The height (h) depends on the “zero level” chosen
where PEg = 0.
A
spoon is raised 21.0 cm above a table. If
the spoon and its contents have a mass of
30 g. what is the gravitational potential
energy associated with the spoon at that
height relative to the surface of the table?
Virtual Lab
Please visit the link below, and fix the setting of the experiment exactly
as in the figure blow.
https://phet.colorado.edu/en/simulation/energy-skate-park-basics
 What
did you notice about total energy.
while the kinetic and potential energy is
varying with time, Is there any change in
total energy?
 ME
= KE + PEg
• Does not include the many other types of energy,
such as thermal energy, chemical potential
energy, and others
 ME
is not a new form of energy.
• Just a combination of KE and PE


The sum of KE and PE remains constant.
One type of energy changes into another type.
• For the falling book, the PE of the book changed into KE as it
fell.
• As a ball rolls up a hill, KE is changed into PE.
Virtual Lab
Visit the link again, and focus on the variation of kinetic and potential
energy what do you notice ?
https://phet.colorado.edu/en/simulation/energy-skate-park-basics
Virtual Lab
What did you find about the variations of kinetic and potential energy?
https://phet.colorado.edu/en/simulation/energy-skate-park-basics
Click below to watch the Visual Concept.
Visual Concept
 Acceleration does not have to be constant.
 ME is not conserved if friction is present.
• If friction is negligible, conservation of ME is
reasonably accurate.
 A pendulum as it swings back and forth a few times
 Consider
friction.
a child going down a slide with
• What happens to the ME as he slides down?
 Answer: It is not conserved but, instead, becomes less and
less.
• What happens to the “lost” energy?
 Answer: It is converted into nonmechanical energy
(thermal energy).
 Answer
the question which is sent via
webex polling.
Let’s watch the following video about
conservation of energy
https://www.youtube.com/watch?v=kP7q28wQ2P8
A
small 10.0 g ball is held to a slingshot
that is stretched 6.0 cm. The spring
constant is
2.0  102 N/m.
• What is the elastic potential energy of the
slingshot before release?
• What is the kinetic energy of the ball right after
the slingshot is released?
• What is the ball’s speed at the instant it leaves
the slingshot?
• How high does the ball rise if it is shot directly
upward?
Kahoot time
https://create.kahoot.it/details/duplicateof-law-of-conservation-ofenergy/09a70e8a-d747-475f-a140e466bb70364e