Chapter 4
Energy and Fields
Choose a system and identify its energy changes before deciding which force, displacement or time interval to use.
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Account for energy stores and transfers
Choose a system boundary and use conservation without counting a transfer and its resulting store increase twice.
Work and kinetic energy
Use force and displacement directions, derive kinetic energy and distinguish pulling work from net work.
Field strength, patterns and force
Define gravitational and electric field strength and interpret uniform and radial field lines.
Field work and potential energy
Relate field force and displacement to gravitational or electric potential-energy changes, including either charge sign.
Elastic energy from a force-extension graph
Calculate stored elastic energy from graph area and state when loading work is recoverable.
Power, losses and efficiency
Distinguish energy from power, use the force component along motion and compare useful output with total input.