Potential and kinetic energy

1. SAN SALVADOR HIGH SCHOOL
MASINLOC DISTRICT
Prepared by:
JEVY ROSE M. MAYONTE
Teacher III

2.  Differentiate potential from
kinetic energy
 Solve and analyze problems
involving potential and
kinetic energy
Least Mastered Skills

3. Overview…
 Kinetic Energy
is the energy
of MOTION
 Potential
Energy is
STORED energy.
• The ability of a system to do work.

4. Kinetic Energy
 The energy of motion that is released from stored energy.
Examples:
An arrow released
from the bow,
flying through the
air.
An object
rolling down
a hill.
Muscles
moving.
A car
moving.

5. Potential Energy
 Energy that is stored in matter, waiting to be released.
Examples:
An arrow being
stretched by a bow
before it’s released
A rock at the
top of a hill
Food for our
bodies.
Fuel for our
automobiles

6. Calculating Potential
Energy
PE= mgh
wherein : m = mass
g = acceleration due to gravity =
Or you could multiply weight (in Newton’s) by height
GPE= wh
wherein : w= weight
h = height
9.8 m/s2
PE = m g h
m g
PE = F h
h
PEg
g
gw

7. Step # 2: Write the formula.
PE= mgh
Step # 3: Substitute the given values.
PE= mgh
PE= 75 kg (9.8 m/s2) (300 m)
PE= 220,500 J
Sample Problem No. 1
A 75 kg refrigerator is located on the 70th floor of a skyscraper (300
meters above the ground). What is the potential energy of the
refrigerator?
Step # 1: Identify the given
m = 75 kg g = 9.8 m/s2
h = 300 m
PE= ?

8. Sample Problem No. 2
A rock on top of a 300 m cliff weighs 20 N. What is the GPE of the
rock?
Given:
h= 300 m
w= 20 N
GPE= ?
Solution:
GPE= wh
GPE= 20 N (300m)
GPE= 6000 N.m or J

9. Calculating Kinetic
Energy
9.8
2
5.0 velocitymassKE 
or KE= ½ mv2
 Unit: Joule
 Named after: James Prescott Joule
 He discovered the relationship between heat
(energy) and mechanical work which led to the law
of conservation of energy.
 How do we derive this unit?
 1 Joule = 1kg ∙ m2/s2
 KE = ½ ∙ m(kg) ∙ v(m/s) 2

10. Step # 2: Write the formula.
KE= ½ mv2
Step # 3: Substitute the given values.
KE= ½ mv2
KE = ½ (3 kg) (7.5 m/s) 2
Sample Problem No. 1
A 3 kg ball is thrown with a velocity of 7.5 m/s. What is the
kinetic energy of the ball?
Step # 1: Identify the given
m = 3 kg
v = 7.5 m/s
KE= ½ (168.75 kg m 2 /s 2 )
KE= 84.38 J

11. Sample Problem No. 2
Determine the kinetic energy of a 1000 kg roller coaster car that is
moving with a speed of 20 m/s.
Given:
M= 1000 kg
V= 20 m/s
KE= ?
Solution:
KE= ½ mv2
KE = ½ (1000 kg) (20m/s) 2
KE= ½ ( 400,000 kg m 2 /s 2 )
KE= 200,000 J

12. Direction: Classify the following energy examples whether potential or kinetic and place them on the forms
of energy Mats. Record your answers on the recording sheet.

13. Recording Sheet

14. Direction: Classify the following energy examples whether potential or kinetic and place them on the forms
of energy Mats. Record your answers on the recording sheet.

15. Recording Sheet

16. 1. Calculate the kinetic energy of a charging elephant
if its mass is 5,000 kg and it moves at 8 m/s.
______________________________________________________________________
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2. Study the information , then answer the question below.
height of drop= 10 m
Mass of ball = 0.05 kg
g= 10 N/kg
Question: What is the GPE of the ball just before it is dropped?
_________________________________________________
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Direction: Solve the following. Show your complete solution.

17. Determine whether the objects in the following problems have kinetic or
potential energy. Then choose the correct formula to use:
KE = 1/2 mv2 OR PE = mgh = Fwh
1. You serve a volleyball with a mass of 2.1 kg. The ball leaves your hand with
a speed of 30 m/s. The ball has ____________ energy. Calculate it.
2. A baby carriage is sitting at the top of a hill that is 21 m high. The carriage
with the baby weighs 12 N. The carriage has ____________ energy. Calculate
it.
3. A car is traveling with a velocity of 40 m/s and has a mass of 1120 kg. The
car has ___________energy. Calculate it.
4. A cinder block is sitting on a platform 20 m high. It weighs 79 N. The block
has _____________ energy. Calculate it.
Assessment Card #2

18. A. Direction: Put a happy face if the given illustration shows kinetic energy and sad
face if the given illustration shows potential energy in the following situations. Write
your answer on the space provided for.
1. A stretched rubber
band
___________________
5. A drawn bow and
arrow
__________________
2. Water at the top of a
waterfall
________________________
6. A yoyo held in your
hands
__________________
3.
_______________
4. _________________
7.______________ 8.________________

19. When these objects move at the
same speed, which will have
more kinetic energy?
If I want to drop an apple
from the top of one of these
three things, where will be
the most potential energy?
A. Direction: Analyze the following activities/situations inside the box. Answer the process question in
each illustration and explain each situation to prove your answer.
Which object has more
kinetic energy?
When does the train on this
roller coaster have the MOST
potential energy?
A water bottle is knocked off a desk.
When does the bottle have the MOST
kinetic energy?
Which object has more
potential energy?
A. B.
A. B. C.
A. B.
A.
B.
A. At the top of the fall.
B. In the middle of the fall.
C. At the bottom of the fall.

20. 1. A bus driving down
the street
2. Going down a slide
3. A train traveling
down the track
4. Someone pushing a
cart
1.Dominoes standing in a
row
2. A rock at the edge of a
cliff
3. Holding a baseball bat
4. A parked car
5.A stretched rubber band

21. Awesome!!!
1.Roller coaster going down
the tracks
2. Slinky moving down the
stairs
3. Swinging a baseball bat
4. Dominoes falling
5. Hitting a volleyball over
the net
6. Riding a skateboard
1. Holding a soccer ball
in place
2. Standing bowling
pins
3. Sitting at the top of
the slide

22. 1. Given:
m= 5000 kg
V= 8 m/s
KE= ?
Solution:
KE= ½ mv2
KE = ½ (5000 kg) (8m/s) 2
KE= ½ ( 400,000 kg m 2 /s 2 )
KE= 160,000 J
2. Given:
height of drop= 10 m
Mass of ball = 0.05 kg
g= 10 N/kg
GPE=?
Solution:
GPE= mgh
GPE= 0.05kg (10 N/kg)(10 m)
GPE= 5 N.m or J

23. Awesome!!!
1. Kinetic Energy
KE= ½ mv2
KE= ½ (2.1 kg) (30 m/s) 2
KE= 945 J
2. Potential Energy
PE= Fwh
PE= 12 N (21 m)
PE= 252 N. m or J
3. Kinetic Energy
KE= ½ mv2
KE = ½ ( 1120 kg) (40 m/s) 2
KE = 896,000 J
4. Potential Energy
PE=Fwh
PE= 79 N (20 m)
PE= 1,580 N.m or J

25. Awesome!!!
A 1. This brick has more mass than the feather;
therefore more potential energy!
2. The higher the object, the more potential energy!
3. The faster the object moves, the more kinetic energy is produced.
The greater the mass and speed of an object, the more kinetic energy
there will be.
4. The semi- truck has more mass;
therefore, more kinetic energy!
5. At the bottom of the fall. It has the most kinetic energy when its
movement and speed are greatest, which is at the bottom of the fall right
before it hits the ground. When an object has the LEAST potential energy is
when it has the MOST kinetic energy.
6. AT THE VERY TOP! The HIGHER the train is lifted by the motor, the
MORE potential energy is produced.
At the top of the hill the train has a huge amount of potential energy,
but it has very little kinetic energy.

26. I want to learn more about potential
and kinetic energy
I should find another evidence…
Science-Grade 8
Learner’s Module pp.26-34
Reprint Edition 2014,2016
ISNB:978-971-9990-72-7
http://www.youtube.com/watch?v=8abzpXCjyjA
Science & Technology IV: Physics Textbook for Fourth
Year.Rabago, Lilia M.,Ph. D.,et al.,2001.pp. 171-174
Science & Technology IV. Physics
Textbook.NISMED.2012. pp.310-314

27. YOU’RE NOW A CERTIFIED