How do I revise E2E stub topic for OCR A-Level?

Always draw a system diagram to identify energy stores and transfers; label all forces doing work and indicate the direction of motion.

What exam tips are there for E2E stub topic? (2)

When tackling problems involving non-conservative forces, use work-energy theorem: net work done = change in kinetic energy.

What exam tips are there for E2E stub topic? (3)

For efficiency questions, write the ratio as useful output ÷ total input × 100%, and check that the result is plausible (e.g., not exceeding 100%).

What mistakes should I avoid in E2E stub topic?

Confusing work done with force alone, neglecting the component of force in the direction of displacement.

What are common errors in E2E stub topic exams? (2)

Misapplying conservation of energy when non-conservative forces (e.g., friction, air resistance) do work, leading to energy 'loss' as thermal energy.

E2E stub topic

OCR

A-Level

This subtopic explores the interconnected concepts of work, energy, and power, foundational to understanding physical systems and mechanical processes. Students examine how work done by a force transfers energy, the principle of conservation of energy, and the calculation of power as the rate of energy transfer. Practical applications include analysing the efficiency of machines and solving real-world problems involving kinetic, gravitational potential, and thermal energy.

Objectives

Exam Tips

Pitfalls

Key Terms

Mark Points

What You Need to Demonstrate

Key skills and knowledge for this topic

Award credit for correctly calculating work done from a force–displacement graph, including interpreting the area under the curve.
Expect clear use of the formula W = Fd cos θ, with correct identification of the angle between force and displacement.
Require explicit statement of energy conservation and correct substitution of values into mgh = ½ mv², with appropriate derivations.
Mark for correct unit conversion (e.g., kJ to J) and final answers expressed with appropriate significant figures.
For efficiency calculations, award credit for correctly identifying useful output energy and total input energy, and for presenting efficiency as a percentage less than or equal to 100%.

Marking Points

Key points examiners look for in your answers

Award credit for correctly calculating work done from a force–displacement graph, including interpreting the area under the curve.
Expect clear use of the formula W = Fd cos θ, with correct identification of the angle between force and displacement.
Require explicit statement of energy conservation and correct substitution of values into mgh = ½ mv², with appropriate derivations.
Mark for correct unit conversion (e.g., kJ to J) and final answers expressed with appropriate significant figures.
For efficiency calculations, award credit for correctly identifying useful output energy and total input energy, and for presenting efficiency as a percentage less than or equal to 100%.

Examiner Tips

Expert advice for maximising your marks

💡Always draw a system diagram to identify energy stores and transfers; label all forces doing work and indicate the direction of motion.
💡When tackling problems involving non-conservative forces, use work-energy theorem: net work done = change in kinetic energy.
💡For efficiency questions, write the ratio as useful output ÷ total input × 100%, and check that the result is plausible (e.g., not exceeding 100%).
💡Show all steps in calculations, including rearranging equations, to secure method marks even if the final answer is incorrect.

Common Mistakes

Pitfalls to avoid in your exam answers

Confusing work done with force alone, neglecting the component of force in the direction of displacement.
Misapplying conservation of energy when non-conservative forces (e.g., friction, air resistance) do work, leading to energy 'loss' as thermal energy.
Incorrectly assuming that power is constant in situations with variable force or velocity; using P = Fv without considering whether v is constant.
Forgetting to convert units (e.g., grams to kilograms) before carrying out energy or work calculations, resulting in order-of-magnitude errors.

Key Terminology

Essential terms to know

Work done by a force

Conservation of energy

Kinetic and potential energy

Power and efficiency

Energy transfer in mechanical systems

Ready to test yourself?

Practice questions tailored to this topic

E2E stub topic

What You Need to Demonstrate

Marking Points

Examiner Tips

Common Mistakes

Key Terminology

Ready to test yourself?

Related Topics in OCR A-Level Physics

Module 1 – Development of practical skills in physics

Module 2 – Foundations of physics

Module 3 – Forces and motion

Module 4 – Electrons, waves and photons