AP Physics 1 Unit 2 Progress Check: Force and Translational Dynamics walkthrough.
About 30 multiple-choice questions and four free-response questions is what College Board puts in this one, and those four are one of each type the AP Physics 1 exam itself uses. That makes it the longest of the eight Progress Checks in the course, where the other seven run about 18 questions each. Explanations only, never AP Classroom answer keys.
What Unit 2 covers
College Board organizes Unit 2 as nine topics, and the Progress Check is drawn from them. The unit is worth 18–23% of the exam’s multiple-choice section, and that scope is not a detail: College Board prints it in the heading above its own weighting table. Unit 3 carries the same band, so the two are tied for the heaviest unit and neither is the heaviest on its own. You can browse every AP Physics 1 unit Progress Check if you are working through the course in order.
The multiple-choice section
College Board publishes the size of this Progress Check in two places in its Course and Exam Description, and each prints the figure with a tilde in front: roughly 30 multiple-choice questions. Every other unit in AP Physics 1 gets roughly 18, so Unit 2 is the one Progress Check that is materially longer than the rest.
One thing shapes how the multiple choice is written. Across the whole exam, the practice College Board calls Creating Representations is listed N/A against the multiple choice: drawing a diagram, plotting a graph or sketching a curve earns points in the free-response section or nowhere. On the multiple choice a free-body diagram is a tool for getting the answer right, never a thing you are scored on. Here is what the questions keep asking.
The four free-response questions
The Unit 2 Progress Check carries four free-response questions, and College Board lists them as one of each type that appears on the exam. That is the useful part: the Progress Check is not a generic quiz, it is a rehearsal of the four question formats in order.
Those point values belong to the exam, not to the Progress Check. College Board publishes no scoring data for any Progress Check, so treat the numbers as what each format is worth when it counts.
College Board is unusually direct about one of them. On the Qualitative/Quantitative Translation question it says that a free-body diagram may well help you work out the acceleration of a system, but that the points are awarded for the explanation and the conclusions the diagram leads to, or for the derivation that comes out of it, rather than for producing the diagram. Its own skill list for that question backs this up: the question is built on deriving, predicting, claiming and justifying, and no drawing skill appears in it at all. The unit that teaches the free-body diagram ends at the question where drawing one earns nothing.
What you are handed on exam day
Several things students try to memorize for this unit are printed and given to them. The AP Physics 1 table of information includes the system acceleration relationship, gravitational force between two masses, the friction inequality, the spring force, centripetal acceleration as v squared over r, and the center-of-mass expression. If you are drilling those to recall, you are drilling the wrong thing; what is worth practicing is choosing which one applies.
The same sheet states four conventions that hold for every question unless a question says otherwise, and three of them decide what belongs on a Unit 2 free-body diagram. The frame of reference is taken to be inertial. Air resistance is taken to be negligible. Springs and strings are taken to be ideal. Read that as an instruction: unless a question tells you otherwise, a drag force does not go on your diagram and a string does not have mass.
What College Board says is out of scope
Unit 2 carries six boundary statements in the course and exam description. They are worth more than they look, because each one is College Board telling you where to stop.
Where the points actually went in 2025
College Board publishes no error data for Progress Checks, so anyone ranking Unit 2 mistakes is guessing. What it does publish is the chief reader report on the real exam, which gives a mean for every single point. On the 2025 exam the fourth free-response question ran on fluids and Newton’s laws, and the pattern in it is a Unit 2 pattern.
A large share of responses wrote as though buoyancy were acting alone on the submerged block. Only about a third of students noted that the gravitational force on the object had not changed. Correct responses put two forces into the net force equation rather than one, and the point that asked for exactly that was the lowest-scoring point on the question, earned by roughly a third of students. The losses were not in the drawing. They were in the force list and in where the system boundary was drawn.
Two things are worth stating beside that so it is not read as a ranking. These were exam questions, not Progress Check questions. And measured as a share of its own points, that fourth question was the best-answered of the four in 2025, while the first was the weakest. Neither figure makes one question harder than another.
How to work through this unit
Draw the diagram first and draw it the way College Board describes: one arrow per force, from the dot, in the direction the force acts. Then write the second law once per object rather than once per problem. Choose a coordinate axis along the direction the object accelerates. That is the general form of the advice usually given about inclines, and on a slope it splits the weight into mg sinθ along the surface and mg cosθ into it.
When you have finished, put the score into our Physics 1 AP calculator to see roughly which of the five AP scores it maps to, then open the AP Physics 1 Review for the exam format and a study plan.
Getting the answers the right way
Progress Check answers are not ours to publish, and the copies circulating on document-sharing sites are usually out of date, often wrong, and always a reason your teacher stops assigning them. There are two legitimate routes, and both are better than a PDF.
Your teacher controls whether solutions are released in AP Classroom. Once they are, you get the worked answer together with the reasoning College Board attaches to each choice, wrong ones included, which is the part a leaked file never has. Ask for the release after the deadline rather than looking for the file. And AP Classroom reports your results by topic, so the more useful question is not which item you missed but which of the nine topics above you missed it in.
Frequently asked questions
Quick answers, checked against College Board.
Does the Unit 2 Progress Check count toward your AP score?
No. Nothing you do in a Progress Check reaches the score colleges see. It is diagnostic work your teacher assigns, and its job is telling you where to go back before May.
Can you use a calculator on the AP Physics 1 exam?
Yes. College Board’s policy table allows a four-function, scientific or graphing calculator on both sections, plus a built-in Desmos calculator in Bluebook. Only three courses carry a 2027 restriction, and Physics 1 is not one of them.
When is the AP Physics 1 exam, and how is it taken?
Wednesday, May 5, 2027, in the afternoon session. College Board runs it as a hybrid: the multiple choice is done inside Bluebook, the free-response prompts are displayed there too, and the written answers go on paper in a booklet.
Has the AP Physics 1 exam changed recently?
Yes, starting with the May 2027 administration. College Board’s clarifications document records the multiple choice moving from 40 items to 42 and from 80 minutes to 85, and the free-response timing shortening from 100 minutes to 95.
Do you publish AP Physics 1 Unit 2 answer keys?
No. Reposted keys go stale, skip the rationale, and are the reason some teachers stop releasing solutions at all. What Curve publishes is the reasoning and the traps.