The 2026 AP Physics C: Mechanics Exam scores:
5: 20%; 4: 25%; 3: 27%; 2: 17%; 1: 11%
The 2026 AP Physics C: Mechanics exam was taken by ~70,000 students — less than 1% of the U.S. high school population.
Multiple-Choice Questions
Students soared through the questions related to Linear Momentum (Unit 4): an impressive 41% earned perfect scores across this topic area.
Students also generally scored well on questions related to Unit 5 (Torque and Rotational Dynamics) and Unit 6 (Energy and Momentum of Rotating Systems). Students achieving AP 5s typically missed no more than a single point across all of these questions.
Free-Response Questions
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FRQ #1, a question about Velocity-Dependent Resistive Forces, Normal Force, Friction, and a Sliding Cube Inside a Decelerating Box, opened the exam with a rich, multi-layered application of Newton’s second law. A box of mass M decelerates horizontally under a resistive force F_r = −bv, while a cube of equal mass M remains against the box’s interior right wall. Because the resistive force is velocity-dependent, the deceleration is not constant — it decreases over time as the system slows — and so the normal force F_N exerted on the cube by the wall decreases with time as well. The nonzero normal force causes friction between the cube and the wall, preventing the cube from moving down the wall until the normal forces decreases to a critical value. In Part A, students determined the acceleration of the cube in terms of F_N, derived F_N as an explicit function of time (requiring them to solve the equation of motion for the decelerating box-cube system, yielding F_N = ) 1/2 b(v_0)e^(-bt/2M) for the combined system), and sketched the frictional force on the cube versus time — a curve that begins at a constant value and later decreases exponentially, proportional to F_N, after static friction can no longer support the cube’s weight. In Part B, students derived t_crit, the moment when the decreasing friction force can no longer support the cube’s weight against gravity, which requires setting the maximum static friction equal to Mg and solving for the time at which the exponentially decaying F_N causes the friction force to cross that threshold.
This was an exceptionally challenging FRQ, by far the toughest of this year’s exam, aimed at providing the most advanced students – students qualifying for AP 5s -- with opportunities to demonstrate their knowledge and thereby differentiate themselves from students receiving other scores, who could not typically earn most of the possible points across this beast of an FRQ.
FRQ #2, the longest question on the exam (suggested 30 minutes), about Projectile Motion, Midair Explosion, Momentum Conservation, and Center-of-Mass Kinematics, requires students to translate concepts across several different representations. A projectile of mass 4M is launched at angle θ with speed v_0; at the apex of its trajectory, it explodes into Piece Q (mass M) and Piece R (mass 3M), with the pieces separating horizontally. Piece Q lands back at x = 0; Piece R lands at x = x_2. Across four parts, students drew scaled momentum bar diagrams for each piece at the moment of explosion — requiring them to apply momentum conservation graphically and recognize that Piece Q’s horizontal momentum is one fourth the magnitude of and opposite to the center-of-mass momentum, and that both pieces have zero vertical momentum at the apex — then derived a symbolic expression for x_2 starting from conservation of momentum, extended a velocity-vs-time graph from pre-explosion through post-explosion for both pieces and the center of mass (Piece Q moving backward at speed (v_0)cosθ to land at x = 0, Piece R moving forward faster than (v_0)cosθ, and the center of mass continuing at (v_0)cosθ as required by Newton’s first law for the system), and finally reasoned whether Piece R lands farther when Piece Q instead drops straight down — correctly concluding x_new < x_2 because Piece Q retaining zero horizontal velocity results in less horizontal momentum for Piece R than when Q moves backward.
This was a challenging question, and provided students earning AP scores of 3+ with multiple opportunities to earn points and show their proficiency in calculus-based physics, differentiating themselves from students receiving AP 2s, who generally earned just 1 of the available points here.
FRQ #3, a question about Kinetic Friction Measurement with a Spring and Block, and Spring Constant Determination via Energy Conservation, challenged students across two experiments. In Experiment 1 (Parts A and B), a block of known mass m rests against a spring of known constant k; beyond position x = 0, there is friction. Students — with only a meterstick — identified which distances to measure, proposed an uncertainty-reduction method, and designed a linearizing graph: by measuring the initial compression x_0 and the distance d the block slides before stopping on the rough surface, energy conservation gives 1/2 k(x_0)^2 = (μ_k)mgd, so plotting x_0^2 vs. d yields a line whose slope is 2(μ_k)mg/k. In Experiment 2 (Parts C and D), a new spring k_new launches a 2.0 kg block up a ramp with negligible friction; students measure maximum height h for five compression distances s and are given five (s, h) data pairs. Energy conservation gives 1/2(k_new)s^2 = mgh, so plotting h vs. s^2 yields a line through the origin with slope k_new/(2mg). Students graphed the data, drew a best-fit line, and extracted k_new from the slope.
Students overall earned higher scores on this FRQ than any of the others on this year’s exam, and provided students across the range of AP 2-5 with opportunities to show how far they could go along the spectrum of skills measured by this FRQ, as the distribution of points across these different levels of proficiency was very even.
Part B served to differentiate AP 4s and AP 5s from other students, as this was the most difficult section of this FRQ. In turn, Part D served to differentiate AP 4s from AP 3s, as AP 3s generally found Part D to be beyond their skills.
FRQ #4, a question about Rotational Dynamics, Work-Energy Theorem, and the Effect of Crank Arm Length on a Unicycle Wheel, asked students to reason about three scenarios involving a unicycle wheel of rotational inertia I_W being spun by a crank arm with a constant perpendicular force F. In Scenario 1 (crank arm length ℓ_1), in Scenario 2 (crank arm length ℓ_2 > ℓ_1), and in Scenario 3 (the wheel on the ground, free to roll without slipping). In Part A, students indicated that ω_2 > ω_1 and justified conceptually that the longer crank arm exerts a greater torque and does more work over one full rotation (the force travels a larger arc length 2πℓ_2 vs. 2πℓ_1), so the wheel gains more rotational kinetic energy. In Part B, they derived ω_1 from the work-energy theorem: the work done is F·2πℓ_1 (force times arc length of one rotation), setting this equal to 1/2 (I_W)(ω_1)^2 and solving. In Part C, students argued that ω_3 < ω_1 because when the unicycle is on the ground, the same applied torque must now also accelerate the translational motion of the unicycle — the wheel’s rotational kinetic energy and the system’s translational kinetic energy are both supplied by the same work input F·2πℓ_1, leaving less energy available for rotation alone.
Students receiving AP 2s could typically begin the question and earn a point, but it was sufficiently challenging to serve primarily for providing a range of difficulties well suited to distinguishing between AP 3s, 4s, and 5s.
All subjects' AP score distributions for 2026 will be posted here when available:
apstudents.org/score-distrib…