Energy - Forces Doing Work | Edexcel GCSE Combined Science Physics, Foundation tier (1SC0)
Energy - Forces Doing Work
- 98 questions
- 7 subtopics
- Paper 6
- Paper 6
Energy – Forces Doing Work is examined in Paper 6, Physics 2.
It covers energy stores and energy transfer diagrams, changing a system's energy, and measuring work done, work done and the energy changes it causes, gravitational potential and kinetic energy calculations, dissipation and wasted energy, power as the rate of energy transfer and the watt, and calculating efficiency.
Sample questions from Energy - Forces Doing Work
Answer each one closed book first, then open the answer.
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Energy stores and energy transfer diagrams
Describe the change in energy stores as a bouncing ball rises after hitting the ground.
Show the answer
Energy is transferred from the elastic potential store of the squashed ball to its kinetic and gravitational potential stores. -
Energy stores and energy transfer diagrams
Explain why the total energy of a sealed, insulated box of moving marbles does not change as the marbles collide.
Show the answer
No energy crosses the boundary, so the energy simply moves between kinetic and thermal stores inside the box. -
Changing a system's energy, and measuring work done
Explain why pushing a car and switching on an electric heater are both described as changing the energy of a system.
Show the answer
Both transfer energy into the system, one through a force doing work and the other by heating. -
Changing a system's energy, and measuring work done
Give the unit in which work done is measured.
Show the answer
The joule, J. -
Work done and the energy changes it causes
Explain why no work is done on a bag that is carried horizontally at a steady height.
Show the answer
The upward force supporting the bag acts at right angles to the motion, so there is no movement in the direction of that force. -
Work done and the energy changes it causes
A braking force of 500 N acts over 20 m to stop a car. Calculate the energy transferred out of the kinetic store of the car.
Show the answer
Work done = 500 × 20 = 10 000 J, so 10 000 J leaves the kinetic store. -
Gravitational potential and kinetic energy calculations
Calculate the gravitational potential energy lost by a 0.15 kg apple that falls 4 m from a tree, taking gravitational field strength as 10 N/kg.
Show the answer
ΔGPE = 0.15 × 10 × 4 = 6 J. -
Gravitational potential and kinetic energy calculations
A bat does 25 J of work on a 0.5 kg ball that was at rest. Calculate the speed at which the ball leaves the bat.
Show the answer
½ × 0.5 × (speed)² = 25, so (speed)² = 100 and the speed is 10 m/s.
The 7 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| Energy stores and energy transfer diagrams | Store changes for a catapult, a fan, a parachutist, a rocket, a clockwork toy and a bouncing ball, what energy transfer diagrams show, and closed systems. | 17 |
| Changing a system's energy, and measuring work done | The three ways a system's energy changes, by forces doing work, electrically and by heating, with examples of each, measuring work done with a newtonmeter and a distance, and work done as energy transferred in joules. | 12 |
| Work done and the energy changes it causes | The work done equation with force and distance calculations, why the distance is along the force, and the store changes when work lifts, drives, brakes or stretches something. | 18 |
| Gravitational potential and kinetic energy calculations | Gravitational potential energy from mass, field strength and height, why lifting work equals the gain, kinetic energy from mass and speed, and finding speed or mass from an energy. | 14 |
| Dissipation and wasted energy | Friction and heating in bicycle gears, lift motors, car engines, drills and tyres, where dissipated energy goes, and why warming a machine's own parts is wasteful. | 12 |
| Power as the rate of energy transfer | Power as energy transferred each second, comparing motors, cranes and heaters, the watt, the power equation, and calculations from work done and time. | 13 |
| The watt, and calculating efficiency | One watt as one joule per second, energy from power and time, and efficiency from useful and total energy or power, as a decimal or a percentage. | 12 |
How the guide is worked
Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.
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Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
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Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
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Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.
Read the full method, the return schedule and the research behind it.
Nearby topics
Edexcel GCSE Combined Science Physics, Foundation tier Active Recall Guide
Every topic, not just this one. 1,297 questions with their answers.