The 2021 paper keeps the classic format of 40 questions in 45 minutes with mechanics at the center, and Division 1 and Division 2 ranked separately. Scan the QR code for the full paper with answers and worked solutions.
The 25 online practice questions start instantly; the full past-paper & answers PDF is available free from an advisor via the QR code — it is not a direct download on this page.2021 Physics Bowl paper overview and exam highlights.
The 2021 Physics Bowl kept the familiar AAPT framework: 40 multiple-choice questions in 45 minutes, points for correct answers with no penalty for wrong ones, calculators allowed, and the paper entirely in English. Division 1 serves freshmen and first-year physics students with no calculus, while Division 2 serves sophomores and AP Physics C students, and the two divisions are ranked and awarded separately.
In overall style the paper stayed anchored to the core high school physics framework. Mechanics, including kinematics, Newton laws and momentum-energy, remained the main scoring ground; electromagnetism leaned on classic models of fields and circuits; and the heat, waves-optics and modern physics items sat at the gentler end of the scale, with few if any trick questions.
When preparing with this paper, train the combination of speed and accuracy: the pace is about 67 seconds per question, so bank the easy marks first and spend the time you save on the multi-step items. Scan the QR code for the complete 2021 paper with the answer key and solutions, and pair it with the 25 original practice questions on this page.
2021 Physics Bowl main topic areas, weights and emphasis.
Kinematics, Newton laws and momentum-energy run through the paper, with rotation and gravitation weighted toward the later questions.
Basic models of fields and circuits dominate, with capacitors and field superposition in the mid range.
Sound formulas, lens imaging and interference fringes share the load, mostly direct substitutions.
Specific heat, engine efficiency and the ideal gas law appear in fixed, low-difficulty formats.
Photon energy, the photoelectric effect and basic relativity rotate in, concept over computation.
2021 Physics Bowl-style mock questions (Basic · Medium · Hard) — submit to grade and view step-by-step solutions.
A cyclist rides at a steady 8 m/s for 15 s. How far, in meters, does the cyclist travel?
Correct answer: C
Uniform motion: s = vt = 8 × 15 = 120 m. Answer C. Core: distance = speed × time.On frictionless ice, a 48 N horizontal net force acts on a 6 kg puck. What is the magnitude of its acceleration in m/s2?
Correct answer: B
a = F/m = 48/6 = 8 m/s2. Answer B. Core: Newton second law, F = ma.A crane lifts a 400 kg piano 12 m upward at constant speed in 20 s (g = 10 m/s2). What is the average power output of the crane?
Correct answer: D
W = mgh = 400×10×12 = 48000 J, and P = W/t = 2400 W. Answer D. Core: power = useful work divided by time.A 1 kg mass hangs from a vertical spring of stiffness 100 N/m and oscillates. What is the period, approximately, in seconds?
Correct answer: E
T = 2π√(m/k) = 2π√(1/100) ≈ 0.63 s. Answer E. Core: the spring period depends only on m and k.A 12 V battery is connected across a 4 Ω resistor. What current, in amperes, flows through it?
Correct answer: B
I = U/R = 12/4 = 3 A. Answer B. Core: Ohm law, I = U/R.Resistors of 2 Ω, 3 Ω and 7 Ω are connected in series across a 24 V battery. What current flows through the battery?
Correct answer: A
The series total is 12 Ω, so I = 24/12 = 2 A. Answer A. Core: add series resistances before applying Ohm law.A 5 μF capacitor is charged to 12 V. How much charge, in microcoulombs, does it store?
Correct answer: B
Q = CU = 5×12 = 60 μC. Answer B. Core: capacitance definition Q = CU.A sound wave travels at 340 m/s in air. If its wavelength is 0.85 m, what is its frequency in hertz?
Correct answer: E
f = v/λ = 340/0.85 = 400 Hz. Answer E. Core: wave speed = frequency × wavelength.How much heat is needed to raise the temperature of 2 kg of water by 5 ℃? The specific heat of water is 4200 J/(kg·℃).
Correct answer: A
Q = mcΔT = 2×4200×5 = 42000 J. Answer A. Core: substitute directly into the specific heat formula.Green light has a frequency of about 5×1014 Hz. With h = 6.6×10-34 J·s, what is the energy of one photon in joules?
Correct answer: C
E = hf = 6.6×10-34×5×1014 = 3.3×10-19 J. Answer C. Core: photon energy E = hf.A stone is thrown horizontally at 20 m/s from a 45 m high cliff (g = 10 m/s2). How far from the base of the cliff does it land?
Correct answer: A
The fall time is t = √(2h/g) = 3 s, and the horizontal distance is x = 20×3 = 60 m. Answer A. Core: treat horizontal and vertical motion independently.A 2 kg block starts from rest at the top of a smooth 5 m high ramp and slides onto a rough horizontal surface, stopping after 4 m (g = 10 m/s2). What is the friction force on the horizontal surface?
Correct answer: E
All of mgh = 2×10×5 = 100 J goes against friction, so f = 100/4 = 25 N. Answer E. Core: energy conservation, mgh = fd.A 2 kg cart moving at 3 m/s collides with a stationary 4 kg cart and the two stick together. What is their common speed after the collision?
Correct answer: C
v = (2×3)/(2+4) = 1 m/s. Answer C. Core: momentum is conserved in a perfectly inelastic collision.The acceleration due to gravity at the surface of Earth is g = 10 m/s2. A spacecraft climbs to an altitude equal to Earth radius R above the surface. What is the magnitude of gravity there?
Correct answer: E
The distance from the center doubles to 2R, so g′ = g/4 = 2.5 m/s2. Answer E. Core: g scales as 1/r2.A 40 V battery drives a 6 Ω resistor in series with a parallel pair of 3 Ω and 6 Ω. What current flows through the battery?
Correct answer: B
The parallel pair gives 2 Ω, the total is 8 Ω, and I = 40/8 = 5 A. Answer B. Core: reduce the parallel branch first, then the series.A particle of charge 2×10-6 C moves at 500 m/s perpendicular to a uniform 0.4 T magnetic field. What is the magnitude of the magnetic force on it?
Correct answer: D
F = qvB = 2×10-6×500×0.4 = 4×10-4 N. Answer D. Core: for perpendicular entry, F = qvB.In each cycle a heat engine absorbs 800 J from a hot reservoir and releases 600 J to a cold reservoir. What is its efficiency?
Correct answer: C
The work output is W = 800−600 = 200 J, and η = 200/800 = 25%. Answer C. Core: efficiency = useful work divided by heat input.An object is placed 15 cm in front of a converging lens of focal length 10 cm. How far from the lens is the image formed?
Correct answer: D
1/v = 1/f − 1/u = 1/10 − 1/15 = 1/30, so v = 30 cm. Answer D. Core: the lens equation 1/f = 1/u + 1/v.In a double-slit experiment the slit separation is 0.1 mm and the screen is 2 m away. Light of wavelength 500 nm is used. What is the spacing between adjacent bright fringes on the screen?
Correct answer: E
Δy = λL/d = 5×10-7×2/10-4 = 10-2 m = 1 cm. Answer E. Core: fringe spacing Δy = λL/d.One mole of an ideal gas occupies 0.02 m3 at 300 K. Take R = 8.3 J/(mol·K). What is the pressure of the gas?
Correct answer: A
p = nRT/V = 8.3×300/0.02 ≈ 1.25×105 Pa. Answer A. Core: ideal gas law pV = nRT.Point charges of +4 μC and −4 μC sit on the x-axis at x = 0 and x = 60 cm. What is the magnitude of the electric field at the midpoint between them? Take k = 9×109 N·m2/C2.
Correct answer: D
Each charge contributes 4×105 N/C at the midpoint in the same direction, giving 8×105 N/C. Answer D. Core: fields add as vectors.A 10 g bullet moving at 100 m/s embeds itself in a 990 g block hanging at rest, and the combined 1 kg mass swings upward (g = 10 m/s2). What maximum height does it reach?
Correct answer: C
The post-collision speed is v′ = 0.01×100/1 = 1 m/s, and h = v′2/(2g) = 0.05 m. Answer C. Core: momentum conservation first, then energy conservation.A uniform disk of mass 4 kg and radius 0.5 m is free to rotate about its central axis (I = ½MR2). A constant torque of 2 N·m is applied. What is the angular acceleration?
Correct answer: A
I = ½×4×0.52 = 0.5 kg·m2, and α = τ/I = 2/0.5 = 4 rad/s2. Answer A. Core: rotational dynamics, τ = Iα.A metal has a work function of 1.5 eV and is lit by photons of energy 4.0 eV. What stopping potential is needed to halt the fastest emitted electrons?
Correct answer: B
The maximum kinetic energy is 4.0−1.5 = 2.5 eV, so the stopping potential is 2.5 V. Answer B. Core: the stopping potential equals the maximum kinetic energy measured in eV.A guitar string is 0.75 m long and carries transverse waves at 300 m/s. What is the frequency of its second harmonic?
Correct answer: D
The fundamental is f₁ = v/2L = 300/1.5 = 200 Hz, so the second harmonic is 400 Hz. Answer D. Core: string harmonics are integer multiples of the fundamental.Unified Physics Bowl specs, consistent across years.
Division 1 is for first-year physics students (no calculus); Division 2 is for second-year and AP Physics C students. The two divisions are ranked and awarded separately — students must choose one and cannot take both. Pick based on your level; our advisor can help.
Four steps · Overview / Topics / Practice / Prep
Read the 2021 Physics Bowl overview and format specs to grasp the year’s style.
Review the key topics and weights, and locate your weak areas.
Complete the 25 mock questions; submit for auto-grading and right/wrong marks.
Open the step-by-step solutions, learn from mistakes, and scan for full papers to push for national and global rankings.
Prep tips and score-boosting advice for the 2021 Physics Bowl.
Complete one recent paper under strict 45-minute conditions and tally where marks are lost. That error map pinpoints weak spots far better than random drilling, and it previews the pace of roughly 67 seconds per question.
Sort kinematics, Newton laws and momentum-energy work into fixed models such as uniform acceleration, inclines, collisions and circular motion. Mechanics carries the largest share, so fluent models mean instant formula recall.
Fields reward direct formula use, while circuits reward series-parallel simplification and Ohm law. Keep a small daily set so equivalent-resistance work becomes reflex.
Specific heat, gas laws, lens images and interference formulas are one-step substitutions. Build a formula card, review it often, and treat these questions as your bank of safe marks.
Keep the photoelectric equation, half-life and time dilation formulas ready without chasing derivations. Circle the useful data in long stems, answer with the result, and save time for the computation-heavy items.
Frequent questions about the 2021 Physics Bowl papers and answers.
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