AQA spec link: Aiming for Grade 4 LOs: Lesson Overview Resources 5.2 When a force causes an object to move State that energy is measured in joules Starters Practical: Doing through a distance work is done on the object. (J). work. Defining work (5 min) Students define the terms work and working as So a force does work on an object when the Calculate the work done by a force. used in common language. Lead them to the idea of a force being force causes a displacement of the object. Measure the work done by a involved in working. experimentally. Interactive: The work done by a on an object can be (10 min) Ask students to describe some Forces and energy Mathematical work calculated using the equation: situations forces cause changes in energy stores. They should Aiming for Grade 6 LOs: out. explain what factors would affect the size of changes in these stores. work done = force × distance (moved along the Describe the action of frictional forces line of action of on objects and the associated heating Main the force) effect. (40 min) Build on the previous idea of forces causing Doing work Use the equation for work done to [W = F s ] changes in energy stores to introduce the idea of doing work on calculate distances or size of forces. something. Be careful with the definition here it is very specific as work done W in joules (J) – Use repeat values to measure the work opposed to the general term work, with which the students will be force F in newtons (N) done by a experimentally. familiar. Students should perform a few calculations to embed the distance s in metres (m) Aiming for Grade 8 LOs: equation. Students then carry out the practical, including supporting One joule of work is done when a force of one calculations. There will be considerable errors in the experiments, Use the principle of conservation of newton causes a displacement of one metre. which the students should discuss. energy and forces to explain why 1 joule = 1 newton metre. Discuss the heating effect of frictional forces using the examples. objects become heated by frictional These can be supported by practical demonstrations such as hand Students should be able to describe the energy forces. rubbing, bicycle brakes, and so on. transfer involved when work is done. the equation for work done in a wide range of contexts. Work done against the frictional forces acting on Plenaries an object causes a rise in the temperature of the object.
AQA spec link: 5.2 When a force causes an object to move through a distance work is done on the object. So a force does work on an object when the force causes a displacement of the object. The work done by a on an object can be calculated using the equation: work done = force × distance (moved along the line of action of the force) [W = F s ] work done W in joules (J) force F in newtons (N) distance s in metres (m) One joule of work is done when a force of one newton causes a displacement of one metre. 1 joule = 1 newton metre. Students should be able to describe the energy transfer involved when work is done. Work done against the frictional forces acting on an object causes a rise in the temperature of the object. Aiming for Grade 4 LOs: State that energy is measured in joules (J). Calculate the work done by a force. Measure the work done by a experimentally. Lesson Overview Starters Defining work (5 min) Students define the terms work and working as used in common language. Lead them to the idea of a force being involved in working. Forces and energy (10 min) Ask students to describe some situations forces cause changes in energy stores. They should explain what factors would affect the size of changes in these stores. Main Doing work (40 min) Build on the previous idea of forces causing changes in energy stores to introduce the idea of doing work on something. Be careful with the definition here – it is very specific as opposed to the general term work, with which the students will be familiar. Students should perform a few calculations to embed the equation. Students then carry out the practical, including supporting calculations. There will be considerable errors in the experiments, which the students should discuss. Discuss the heating effect of frictional forces using the examples. These can be supported by practical demonstrations such as hand rubbing, bicycle brakes, and so on. Plenaries Resources Practical: Doing work. Interactive: Mathematical work out. Aiming for Grade 6 LOs: Describe the action of frictional forces on objects and the associated heating effect. Use the equation for work done to calculate distances or size of forces. Use repeat values to measure the work done by a experimentally. Aiming for Grade 8 LOs: Use the principle of conservation of energy and forces to explain why objects become heated by frictional forces. the equation for work done in a wide range of contexts.
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