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Unit 3: Work, Energy, and Power

5 dot points across 5 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How is the total energy of a system conserved as it changes form, and how does that let us solve problems without tracking forces over time?

Topic 3.4 Conservation of Energy: apply conservation of mechanical energy to systems with conservative forces, and account for energy dissipated by nonconservative forces such as friction.
A focused answer to AP Physics 1 Topic 3.4, covering conservation of mechanical energy, the interchange of kinetic and potential energy, how friction and other nonconservative forces dissipate energy, and using energy bookkeeping to solve problems, with full worked examples.
11 min answer →

How can energy be stored in the configuration of a system, and how is gravitational and elastic potential energy calculated?

Topic 3.3 Potential Energy: define potential energy as stored energy of a system's configuration, and calculate gravitational potential energy (mgh) and elastic potential energy (1/2 kx^2).
A focused answer to AP Physics 1 Topic 3.3, covering potential energy as stored energy of a configuration, gravitational potential energy mgh near Earth, elastic potential energy 1/2 kx^2, the role of conservative forces and reference points, with full worked examples.
10 min answer →

How fast is energy transferred or work done, and how is that rate calculated?

Topic 3.5 Power: define power as the rate of energy transfer through P = W/t = Delta E/Delta t, and use P = Fv to relate power to force and speed.
A focused answer to AP Physics 1 Topic 3.5, covering power as the rate of doing work or transferring energy, the formulas P = W/t and P = Fv, average versus instantaneous power, and the watt as a unit, with full worked examples.
9 min answer →

What is the energy an object has because it is moving, and how does it depend on the object's mass and speed?

Topic 3.1 Translational Kinetic Energy: define the kinetic energy of a moving object through K = 1/2 mv^2, and reason about how it changes with mass and speed.
A focused answer to AP Physics 1 Topic 3.1, covering translational kinetic energy, the formula K = 1/2 mv^2, why kinetic energy is a scalar that depends on the square of the speed, and how it varies with mass and reference frame, with full worked examples.
9 min answer →

How does a force transfer energy to or from an object as it moves, and how is that energy transfer calculated?

Topic 3.2 Work: calculate the work done by a force through W = Fd cos(theta), connect net work to the change in kinetic energy, and read work as the area under a force-displacement graph.
A focused answer to AP Physics 1 Topic 3.2, covering work as a force acting through a displacement, the formula W = Fd cos(theta), positive and negative work, the work-energy theorem, and work as the area under a force-displacement graph, with full worked examples.
10 min answer →