The shape of the lesson
By the end of the lesson, learners can
- Push along, and transfer energy: Set the force and the distance, then push the load.
- Force, distance, direction: The defining equation:
- Equation: work = force × distance moved in the direction of the force.
- Work done = energy transferred, both in joules.
- Check direction: a force at right angles to the motion does no work.
One picture every idea returns to
Work done = force × distance moved in the direction of the force: W = Fd, measured in joules. The work done is equal to the energy transferred. The force must act along the direction of motion for it to do work.
Forty-five minutes, phase by phase
| Time | Phase | What happens in the room | Grouping |
|---|---|---|---|
| 0 to 5 min | Hook: predict | Open with the question in the title, Work is energy on the move.. Pushing a stalled car, lifting a crate, dragging a sledge: whenever a force shifts something along its own direction, it does work, and that work is exactly the energy it hands over. | Whole class, then pairs |
| 5 to 17 min | Teach and check: Push along, and transfer energy | Set the force and the distance, then push the load. Project tab 2 of the lab (Work done) and let a student drive it while the class predicts. | Whole class, then pairs |
| 17 to 30 min | Teach and check: Force, distance, direction | The defining equation: Model the worked example Worked example on the board, one line at a time. | Rally Coach |
| 30 to 36 min | Check | The four Stage 1 questions from the student lesson, answered on mini whiteboards or by show of fingers. Re-teach the one most get wrong. | Individual, then whole class |
| 36 to 43 min | Plenary | The exam-style questions from Stage 2, one at a time: thirty seconds alone, then a random call. The feedback lines in the key give the examiner's wording. | Individual, random call |
| 43 to 45 min | Exit and homework | Set the worksheet below (6 questions, 12 marks). Learners self-assess against the objectives before they leave. | Individual |
Protect the parts that carry the learning
The sequence carries about fifty minutes of material, so the lab is driven by one student while the class predicts rather than explored freely. Times are a guide.
Protected: the check at 30 minutes. It is the only individual read on whether the key idea landed, and it is not cut.
Cut first if the build overruns: the last check in Force, distance, direction, never the check or the plenary.
In a 60 minute block: run worksheet questions 1 to 3 in class as a Rally Coach set and model both the hardest worked example and its check live.
Rally Coach
Pairs share one worksheet. One partner solves the first question aloud while the other coaches, checking each line and offering a prompt rather than the answer; they swap roles for the next question.
The full structure, with its variations and the other twelve, is on the cooperative-learning page.
What to head off, and how
| Trap learners fall into | Teaching move that pre-empts it |
|---|---|
| A force at right angles to the motion does no work. | When you carry a bag along a level floor, the upward force you apply is vertical while the motion is horizontal, so that force transfers no energy. Only a force with a component along the direction of motion does work. |
Work done (W = Fd): worksheet
6 questions, 12 marks. Written in the style of the papers; no past paper question is reproduced.
Write the equation for work done, state its unit, and state how work done is related to energy.
A force of 30 N pushes a box 5.0 m in the direction of the force. Calculate the work done.
A trolley is pulled 2.5 m along a bench by a steady force of 12 N. Calculate the work done and state the energy transferred.
A person pushes hard against a heavy wall, but the wall does not move. State the work done on the wall and explain your answer.
A waiter carries a tray at a constant height while walking horizontally across a room. Explain why the upward force on the tray does no work.
A steady force of 40 N does 240 J of work pushing a crate. Calculate the distance the crate moves in the direction of the force.
Answer key and marking notes
- W = Fd (force × distance moved in the direction of the force); unit joule (J). ✓
- The work done is equal to the energy transferred. ✓
- W = Fd = 30 × 5.0
150 J
- W = Fd = 12 × 2.5 = 30 J
30 J of energy transferred
- The work done is zero. ✓
- W = Fd, and the distance moved in the direction of the force is zero, so no work is done. ✓
- The supporting force is vertical, but the motion is horizontal. ✓
- There is no movement in the direction of that force, so it does no work. ✓
- W = Fd → d = W ÷ F = 240 ÷ 40
d = 6.0 m
1 multiple-choice questions on this lesson
From the topic question bank. Assign them in the app for a marked score in your gradebook, or run the topic as a class game.
A worker pushes a cart with a steady force of 80 N through a distance of 5.0 m in the direction of the force. How much work is done?
- A16 J
- B85 J
- C400 J
- D4000 J
Quiz key
W = Fd = 80 × 5.0 = 400 J. Option A divides instead of multiplying; B adds the numbers; D adds an extra zero.
What to project
The student lesson embeds these tabs. Open them full screen on the projector; every slider has a drag handle on the stage.
Slides for this lesson
A projectable deck for every pack is on the way. Until then, present the student lesson full screen: its sections, figure and lab tabs follow the same order as the plan above.