02.3 - Work, Energy and Power

Understandings:

• Kinetic energy

• Gravitational potential energy

• Elastic potential energy

• Work done as energy transfer

• Power as rate of energy transfer

• Principle of conservation of energy

• Efficiency

Applications and skills:

• Discussing the conservation of total energy within energy transformations

• Sketching and interpreting force–distance graphs

• Determining work done including cases where a resistive force acts

• Solving problems involving power

• Quantitatively describing efficiency in energy transfers

Guidance:

• Cases where the line of action of the force and the displacement are not parallel should be considered

• Examples should include force–distance graphs for variable forces

Theory of knowledge:

• To what extent is scientific knowledge based on fundamental concepts such as energy? What happens to scientific knowledge when our understanding of such fundamental concepts changes or evolves?

Utilization:

• Energy is also covered in other group 4 subjects (for example, see: Biology topics 2, 4 and 8; Chemistry topics 5, 15, and C; Sports, exercise and health science topics 3, A.2, C.3 and D.3; Environmental systems and societies topics 1, 2, and 3)

• Energy conversions are essential for electrical energy generation (see Physics topic 5 and sub-topic 8.1)

• Energy changes occurring in simple harmonic motion (see Physics sub-topics 4.1 and 9.1)

Aims:

• Aim 6: experiments could include (but are not limited to): relationship of kinetic and gravitational potential energy for a falling mass; power and efficiency of mechanical objects; comparison of different situations involving elastic potential energy

• Aim 8: by linking this sub-topic with topic 8, students should be aware of the importance of efficiency and its impact of conserving the fuel used for energy production