AP Physics 1 · Unit 3 · Energy

Unit 3 Review Practice Problems

Review work, energy, springs, and power through 20 questions. Choose an energy system, combine transfers and stores, and explain motion on rough tracks, ramps, swings, and powered lifts.

20 questions10 conceptual · 10 calculation

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Simulation scene from the Unit 3 Review lesson. — A scene from the related lesson. Open the practice to work through the questions.

What you’ll practice

Choose the energy relationship that fits the task

Identify work and power signs

Compare forces perpendicular to motion, braking forces, and motors at steady speed. Explain how speed changes affect kinetic energy.

Combine energy stores and transfers

Solve drops, spring releases, rough ramps, angled motor pulls, and swings. Choose the reference for gravitational potential energy consistently.

Use graphs and time information

Calculate work from a changing force–position graph. Connect useful lifting work with average power and compare motion at selected points.

A question from this set

A support force on a moving package

A package slides along a frictionless horizontal shelf. The shelf pushes upward on it throughout the slide. What work does that normal force do?

Positive work because the package moves.
Zero work because the force is perpendicular to displacement.
Negative work because the force opposes gravity.

Try it in the practice set

The shelf’s support force is vertical while the package moves horizontally.

Key ideas

Match the energy accounting to the question

Net work describes a change in kinetic energy

Add the work of the forces acting on an object to find ΔK. When using potential-energy stores for a larger system, account for the same interactions within those stores.

Power adds a time or velocity comparison

Work and energy totals do not say how quickly the transfer occurs. Use elapsed time for average power or the current force and velocity for instantaneous power.

See the physics

Test the energy relationships across the unit

Check each response before opening its scene. Compare a supported package, braking cart, projectile, spring-driven cart, swing, and powered cable with the work and energy quantities in your solution.

Use a hint for a starting point or open a worked solution to follow the reasoning. Your progress saves in this browser, so you can return to unfinished questions.

Ready for unit 3 review?

Begin with a conceptual question, then work through the calculations.

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