Year 7 Science · Unit 3 · Lesson 12
Apply Worksheet
Learning Goals
Order the steps
Number the events from 1 to 7 to show the correct order of energy transformations during a roller coaster ride. Event 1 = what happens first. The events are shuffled — put them in the right order.
| Order | Event |
|---|---|
| The car reaches maximum speed at the bottom of the first valley — KE is at its maximum for the ride. | |
| The car is slowly pulled up the first hill by the motor — gravitational PE increases steadily. | |
| The car climbs the second hill — KE converts back to gravitational PE; speed decreases. | |
| Brakes at the end convert remaining KE to thermal energy (heat) and sound — the car stops. | |
| The car sits at the top of the first hill — gravitational PE is maximum for the whole ride, KE is near zero. | |
| The car descends the first hill — gravitational PE converts to KE; speed increases rapidly. | |
| The second hill is lower than the first because some energy was lost to friction and air resistance as heat and sound. |
Scenario
Two identical pendulums are set up in a physics lab. Pendulum A is pulled back so its bob is 30 cm above the lowest point. Pendulum B is pulled back so its bob is 60 cm above the lowest point. Both pendulums are released at the same moment. Ignore air resistance and friction for this question.
(a) Predict: Which pendulum — A or B — will have more kinetic energy when it reaches the lowest point of its swing? State your prediction clearly.
(b) Justify your prediction. Explain the energy transformation that occurs as a pendulum swings from its highest point to the lowest point. Why does a higher starting position result in more kinetic energy at the bottom?
(c) After several swings, both pendulums will swing to a slightly lower height each time. Where is the energy going? Name the forms it is converted to.
1. The Snowy Hydro 2.0 project stores energy by pumping water uphill into an upper reservoir. Explain, step by step, how the energy stored as gravitational PE in the reservoir becomes electrical energy in your home. Name each energy transformation.
2. An Australian pole vaulter bends their pole during the jump, then the pole straightens. Describe the energy transformations that occur from the moment the pole is fully bent to the moment the vaulter clears the bar at maximum height.
Wrap Up
In one sentence, what was the main idea of this lesson?