SPH3U Energy Quiz Review Outline
Test Date: Monday, May 11, 2014 (Day 1 students), Tuesday, May 12, 2014 (Day 2 students)
Format:
8 marks multiple choice, 24 marks short answer (calculate/explain), 32 marks total
All energy unit equations will be provided.
Topics:
Energy and Work, Thermal Energy and Heat:
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What is energy? What is work? Forms of
energy
Work done on, work done by
Work–Energy Theorem
Kinetic energy
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Gravitational potential energy
Law of Conservation of Energy
Power
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What is heat? Kinetic Molecular Theory
Forms of heat transfer – conduction,
convection, radiation
Textbook pages and recommended textbook
questions:
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pp. 215-221, 222-224, 226-227, 228-234,
235-237, 252-257, 260-264, 269-271
p. 221 – #3, p. 241 – #4, 12, 15, 18, 21, 22
p. 226 – #2, 3, p. 242 – #32, 33, 34
p. 228 – #1, 2, 3, p. 243 – #38, 39
p. 243 – #41, 42, 44
p. 242 - #24, 26, 28, p. 244 - #45, 46
p. 275 - #3, 11, 15, 23
The following formulae and constants will be provided:
W  Fd cos
W  Fnet d cos
E g  mgh
W  Ek
1
E k  mv 2
2
All other necessary information will be provided.
g = 9.8 m/s2
P
W E

t
t
Some Energy Problems:
1. Alex DL and Sara push a large crate full of 150 W light bulbs (50 kg) across the floor at constant
velocity with a horizontal force of 200 N [right] over a distance of 8 m. What is the force of friction?
What is the work done by Alex and Sara? What is the work done on the crate? (Answers: 200 N [left],
1600 J, 0 J)
2. The bus (m = 1500 kg) on the band trip has broken down on the highway. Emma and Alex M are
recruited to pull on a harness attached to the front of the bus at an angle of 25 degrees to the ground.
Together they exert a force of 1000 N on the harness and manage to move the bus 240 cm forward.
What is the work done by the dynamic duo on the bus? Assuming the bus starts at rest, what is the
change in kinetic energy of the bus? What is the final velocity of the bus? (Answers: 2175.1 J, 2175.1
J, 1.70 m/s)
3. An object is thrown upwards at an initial speed of 5.0 m/s from a cliff 80 m high. Using conservation
of energy, calculate its velocity when it is 30 m from the ground. Another object of equal mass is
thrown downwards at 5.0 m/s. What is its velocity when it is 30 m from the ground? (Answers: 31.7
m/s, 31.7 m/s)
4. Cara and Isabel emerge from their dungeon workshop with a 15 W lightbulb that they claim uses
43200 J of light energy every hour. How much energy does the lightbulb actually consume in 1 hour?
If they find a way of generating 60 W of power, how many lightbulbs could they actually light?
(Answers: 54,000 J, 4 lightbulbs)
5. A 1000 kg Smart car is traveling at 100 km/h. How much kinetic energy does it have? From how high
above the ground does it need to be dropped for it to have the same amount of kinetic energy upon
hitting the ground? (Answers: 3.86 × 105 J, 39.4 m)
6. Use Kinetic Molecular Theory to explain why water in gas state is more likely to cause burns than
water in liquid state.
7. You pick up a stainless steel pot and a plastic mixing bowl that have both been stored in the same
drawer. Which one feels colder? Explain, using the concepts of heat transfer and thermal
conductivity.
8. A 100 W lightbulb is operated continuously for 1 week. How much energy does it consume?
(Answers: 6.05 × 107 J)