Work, Energy and Power: Roller Coaster Energy Budget

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Science · Physics
SP-PHYS-005  ·  Free to print and use in your classroom  ·  substituteplans.com
Page 2
Work, Energy and Power: Roller Coaster Energy
Budget
Science · Physics · Grades 10-12 · 50 minutes
Time needed
50 minutes (one class period)
Prep
Copy the 2-page worksheet (one per student). Write the formulas and g = 9.8 m/s² on the
board.
Technology
A basic or scientific calculator is recommended (square roots appear in one part).
Student
independence
High. Students work alone, then compare with a partner.
Copies to make
One 2-page worksheet per student
Materials
Pencils, Worksheet, Whiteboard or chalkboard, Calculators (recommended)
Goal for today: Students will use W = F × d, KE = ½mv², PE = mgh and P = W ÷ t to solve problems and will show
that mechanical energy stays constant without friction.
Before the bell
☐ Copy the worksheet, one per student (2 pages).
☐ Write on the board: W = F × d KE = ½ × m × v² PE = m × g × h P = W ÷ t g = 9.8 m/s²
☐ Also write: units — work and energy in joules (J), power in watts (W), force in newtons (N).
☐ Keep the answer key on your desk. You do not need to solve anything yourself.
Say this to start
Good morning! Today’s physics work is about work, energy and power. In physics, work happens when a force moves
something. You will use four formulas that are on the board, and then you will track the energy of a roller coaster car
as it rolls down a hill. Calculators are fine. Show each step and write units.


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Science · Physics
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Run of show
Minutes
What you do
What students do
0–5
Take attendance. Hand out the worksheet.
Settle in and take out a pencil and
calculator.
5–12
Read the formulas on the board aloud. Work this example:
pushing a box with 10 N for 3 m does 10 × 3 = 30 J of
work. Doing that work in 5 s is a power of 30 ÷ 5 = 6 W.
Follow the example.
12–30
Tell students to do Part A (problems 1–7). Walk the room
and point to the formula list when a student is stuck.
Write the formula, substitute, solve, and
add units.
30–42
Tell students to do the coaster table and then Part B
(questions 8–10). For the table, they can use total energy
= PE at the top.
Fill in the table, then answer the questions.
42–47
Read the answers from the key aloud. Students mark their
work.
Check answers and fix mistakes.
47–50
Collect all worksheets in one stack.
Hand in the worksheet.
If things go wrong
• If students ask why the box carried horizontally does no work, tell them the lifting force is up but the motion is
sideways, so the lifting force does no work on it.
• If students get large numbers such as 200000 J, tell them that is normal for a moving car.
• If a student’s coaster table does not add up, tell them PE + KE should be the same at every point (19600 J).
• If students finish early, use the early finisher list.
Early finishers
• Find the kinetic energy of a 60 kg runner moving at 5 m/s.
• Explain in two sentences why a roller coaster’s first hill must be its highest.
Support and challenge
• Support: Have students do problems 1, 2, 3 and 5 and the first two rows of the coaster table.
• Challenge: Use the coaster table to find the car’s speed at a point 5 m above the ground.
Notes for the teacher (you fill this in)
Jot a few lines before you leave. A full Daily Sub Report is in the free Sub Survival Kit at SubstitutePlans.com.
How far the class got / what to pick up next:
Students who were especially helpful:


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Science · Physics
SP-PHYS-005  ·  Free to print and use in your classroom  ·  substituteplans.com
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Anything the teacher should know: