Catalyst – Tuesday 18th
Essential Questions: How are temperature and energy related? Where does energy come
from and where does it go? How is energy converted into different forms?
1. Give two examples of heat convection.
2. Describe specific heat in your own words.
3. Which of the following substances heats up the quickest?
Aluminum = 900 c/J kg K
Copper = 390 c/J kg K
Iron = 470 c/J kg K
4. Do you remember the law of conservation of energy? Define it
in your own words!
Catalyst – Tuesday 18th
Essential Questions: How are temperature and energy related? Where does energy come
from and where does it go? How is energy converted into different forms?
1. Give two examples of heat convection.
Heating system, creamer swirling in coffee
2. Describe specific heat in your own words.
Energy needed to change temperature.
3. Which of the following substances heats up the quickest?
Aluminum = 900 c/J kg K
Copper = 390 c/J kg K
Iron = 470 c/J kg K
4. Do you remember the law of conservation of energy? Define it in your own
words!
Yes, it is when matter cannot be created nor destroyed but ONLY change
form!
Agenda
(10) Catalyst & Answers)
(5) Blocks 3&4 Heat transfer rap video
(10) Specific Heat worksheet
(40) Gallery Notes on KE & PE
(20) Teacher Lecture
(5) Exit ticket
Catalyst – Tuesday 19th
Essential Questions: How are temperature and energy related? Where does energy come
from and where does it go? How is energy converted into different forms?
1. What is the formula for Work?
2. What is the formula for Power?
3. If substance A has a specific heat of 5J/C and substance B has a specific heat of 1 J/C, which one will
heat up quicker?
4. I do 20J of work on a box and move it 5m, what force did I apply to the box?
Unit 8 - Energy
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Heat
Temperature
Thermal Energy
Work
Power
Kinetic Energy
Potential Energy
Law of Conservation of Energy
Energy is neither created nor
destroyed, it can only
change form.
Example: A flashlight - The
energy from the battery is
converted into light energy.
Kinetic Energy
Kinetic Energy is the energy of motion
Write 3 examples of
something that would have
HIGH Kinetic energy.
1. Running
2. Roller Coaster
3. High speed train
Things like:
Kinetic Energy Formula
Kinetic Energy Formula = ½ (mass x velocity2)
KE (J) = ½ m (kg) x v2 (m/s)
1. Calculate the kinetic energy of a running back that has a
mass of 80 kg and is running at a velocity of 8 m/s.
KE=2,560 J
Which has more Kinetic Energy???
1. A bus full of passengers travelling at 25 mph OR an
empty bus at 25 mph
2. A toy car moving at 4 m/s OR a toy car sitting at rest on a
shelf
3. 7kg bowling ball moving down the alley, 7kg bowling
ball at rest.
4. An adult riding a bicycle, a teenager driving a car.
Gravitational Potential Energy
Gravitational potential energy is the stored energy of an object
as a result of it’s position/height .
Higher up = more Potential Energy
Write 3 examples of something that would
have HIGH POTENTIAL energy
1)Basketball player in the air dunking
2)Air plane in the sky
3)Football in the air
Things like:
Gravitational Potential Energy Formula
PEgravitational = mass (kg) x gravity (Ag) x height (m)
2. John has an object suspended in the air. It has a
mass of 50 kilograms and is 50 meters above the
ground. Find its gravitational potential energy.
PEgravitational = 24,500J
Which has more Potential Energy???
1. An empty box sitting on a shelf OR a full box sitting on the same
shelf
2. A 10kg cat at the top of a flight of stairs OR a 3 kg kitten at the top
of the stairs
3. A pitcher throwing a baseball OR a softball on the ground.
4. Roller coaster cart on top of the coast OR cart at the bottom of the
coaster?
Mechanical Energy
Mechanical Energy = Kinetic Energy +Potential Energy
Where does the roller coaster have the most Potential Energy?
W
Where does the roller coaster have the most Kinetic Energy?
X
Where does the roller coaster have the most Mechanical Energy?
W, X, Y,Z
Mechanical Energy....What??!?
• Energy goes through a series of transformation and changes.
• So potential energy turns into kinetic energy and turning back into
potential energy. A small quantity of this energy is transferred as
heat to the wheels and as vibrations that produce a roaring sound in
the air.
• In a mechanical system such as a roller coater or a swinging
pendulum, the energy in the system at any time can be calculated by
adding the kinetic and potential energy to get the total mechanical
energy.
• The law of conservation of energy requires that at any given time,
total energy should be the same.
Friction and Mechanical Energy
Why doesn’t a roller coaster go on forever?
Reasons below…..
Energy is used for other things. Roller coasters produce
heat , the track heats up, etc.
Friction is a force that uses some of the mechanical energy
in a system.
Conceptual Understanding
A penny is dropped off the Eiffel tower. As it falls, what happens
to it’s potential energy? What happens to it’s kinetic energy?
As it falls, it’s velocity increases so …..
However, it loses height so ….
Mechanical energy stays the same in the air because …..
Kinetic or Potential?
1. A car is driving down the highway at 65 mph
2. A car is parking at the top of a hill
3. a rubber band zinged from your finger
4. moving a skateboard
5. A glass of milk
Kinetic & Potential Energy Questions
1. What is the potential energy of a 2-kilogram potted
plant that is 1 meter-high plant stand?
PEgravitational = mgh
PEgravitational = (2kg)(9.8m/s2)(1m)
PEgravitational = 19.6J
2. What is the kinetic energy of a 3-kilogram ball that is
rolling at 2 meters per second?
KE = ½ mv2
KE = ½(3kg)(2m/s2)
KE = 6 J
For the Final…..
Answer:
?
For the Final….
Answer:
?
ET - Kinetic/Potential Energy 3.1.2
1. What is kinetic energy?
2. Object A is sitting 100m above the ground, Object B is sitting 10m
above the ground. They are the same size, which has more potential
energy?
3. Calculate the kinetic energy of a 3 kg car moving 6 km/s
4. Calculate the potential energy of a box that is sitting 2 m above the
ground and has a mass of 2kg
5. Why does a roller coaster lose some energy while running on the
tracks? Where does that energy go?
ET – Wednesday 19th
1. When a rock is dropped from a height of one meter, the
graviational potential energy of the rock is converted to kinetic
energy. When the rock hits the floor and does not bounce, what
happends to the kinetic energy of the rock?
2. When one form of energy is converted into other forms of energy,
what happens to the total amount of energy?