AP Physics 1 free-response questions: how to score well

By Ashraf Bhura, Co-Founder, STEM-Tutor · Updated October 2026

The free-response section is half of your AP Physics 1 score. It rewards clear reasoning more than long calculations, so knowing what readers look for can raise your score quickly.

The format

Since the 2025 exam, AP Physics 1 has two sections. Section I is 40 multiple-choice questions. Section II has four free-response questions in 100 minutes, worth half of the exam score. A graphing calculator and the official equation sheet are allowed throughout. The four FRQs are of four different types, each testing a different skill:

• Mathematical Routines (MR): solve a physics problem using equations, often deriving an expression symbolically and then interpreting it.
• Translation Between Representations (TBR): move between diagrams, graphs, equations and words, for example by drawing a free-body diagram and then writing an equation from it.
• Experimental Design and Analysis (LAB): describe a procedure, choose what to measure and graph, and analyse data to find a physical quantity.
• Qualitative/Quantitative Translation (QQT): explain a situation in words, derive an equation, and check that the two agree.

The College Board can update formats, so check the current Course and Exam Description on AP Central before your exam.

What readers award points for

Each FRQ is marked against a scoring guideline that lists specific points. Points are awarded for physics, not for length. Typical point-earning moves are:

• starting from a correct fundamental equation, such as Newton's second law or conservation of energy;
• substituting correctly, often in symbols rather than numbers;
• stating which quantity changes and which stays constant, and why;
• linking a claim to evidence with a physics principle, such as “because no external net force acts, momentum is conserved”;
• drawing diagrams with the correct forces, labels and relative lengths.

An answer can be short and still earn full marks if every point is present. A long answer that never names the principle can earn very few.

How to write a justification

Many questions ask you to “justify your answer”. A reliable structure is claim, evidence, reasoning:

1. Claim: answer the question directly. “Block A reaches the bottom first.”
2. Evidence: point to the relevant feature of the situation. “Both blocks have the same mass, but the ramp for A is steeper.”
3. Reasoning: connect them with a physics principle. “The component of gravity along the ramp, mg sinθ, is larger for A, so by Newton's second law A has a larger acceleration and covers the same distance in less time.”

Avoid vague words such as “force of motion” or “it has more energy” without saying which energy and why.

Derivations

When asked to “derive an expression”, start from a fundamental equation on the equation sheet, show each substitution, and finish with the requested quantity in terms of the given symbols and physical constants only. Do not substitute numbers unless asked. Readers award points for the starting equation and for each correct step, so a clear derivation can earn most of the points even with an algebra slip at the end.

A worked practice FRQ

This is an original question in the style of a QQT question.

Two carts, each of mass M, are on a level, frictionless track. Cart 1 moves at speed v₀ towards cart 2, which is at rest. The carts stick together.

Part (a): predict without calculation

Will the speed of the carts after the collision be greater than, less than or equal to v₀/2? Justify your answer without equations.

• Claim: equal to v₀/2.
• Reasoning: no external horizontal force acts on the two-cart system, so its total momentum is conserved. After sticking, twice the mass is moving, so to keep the same momentum the speed must be half the original speed.

Part (b): derive

Derive an expression for the speed v_f after the collision in terms of v₀.

• Conservation of momentum: Mv₀ + M(0) = (2M)v_f.
• v_f = v₀/2.

Part (c): consistency

Explain how your answers to (a) and (b) are consistent.

• Both show the final speed is half of v₀. The reasoning in (a) that doubling the mass halves the speed is exactly what the factor of 2M in the derivation expresses.

Part (d): energy

Is kinetic energy conserved in this collision? Support your answer.

• Initial K = ½Mv₀². Final K = ½(2M)(v₀/2)² = ¼Mv₀².
• No: half the kinetic energy is transformed into internal energy (heating and deformation) as the carts stick. Perfectly inelastic collisions always lose kinetic energy, even though momentum is conserved.

Lab (experimental design) questions

For the LAB question, describe a procedure that someone else could follow. Name the measuring tools, say what you will vary and what you will keep constant, and describe how you would reduce uncertainty, for example by repeating trials or measuring over many oscillations. When asked to find a quantity from a graph, choose axes that give a straight line. For a pendulum, T = 2π√(L/g), so plotting T² against L gives a line with slope 4π²/g. Always use points from your best-fit line, not raw data points, to calculate the slope.

Timing

With four questions in 100 minutes, aim for about 25 minutes each. Read every part before you start writing, because later parts often hint at what earlier parts want. If you get stuck on a calculation, write the starting equation and move on; you can still earn points in later parts, which are usually marked independently.

Common mistakes

• Writing numbers when the question asks for a symbolic derivation.
• Giving a claim with no physics principle to support it.
• Drawing free-body diagrams with extra forces, such as a “force of motion”.
• Calculating a slope from data points that do not lie on the best-fit line.
• Leaving a part blank; a correct starting equation often earns a point.

Practice questions

Try each one before opening the answer.

Frequently asked questions

How many free-response questions are on AP Physics 1?

Four, one of each type: Mathematical Routines, Translation Between Representations, Experimental Design and Analysis, and Qualitative/Quantitative Translation.

Where can I find official practice FRQs?

AP Central publishes past free-response questions with scoring guidelines and sample student responses. Marking your work with the scoring guidelines is the best practice there is.

Can I use a calculator on the free-response section?

Yes. A graphing calculator is allowed on both sections of AP Physics 1, along with the equation sheet.

Key takeaways

• Four FRQs in 100 minutes, worth half the exam.
• Points come from principles, equations and clear reasoning, not length.
• Justify with claim, evidence and reasoning.
• Derive symbolically from a fundamental equation.
• Practise with official FRQs and mark them with the scoring guidelines.

Related guides

• How to get a 5 on AP Physics 1
• AP Physics 1 equation sheet
• AP Physics 1 momentum