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Top 200 Vocabulary Word List for AP Physics C: Mechanics | Must Know Words for Common Examination Instructions

The 200-word examination instruction list

AP Physics C: Mechanics asks you to translate a physical model into calculus and explain what the result means. Choose the system and sign convention before differentiating or integrating.

Start with the list or jump to exam requirements, worked examples, the Fencing Method or practice. The list combines task verbs with subject terms that help you interpret the question.

Essential instructions

No.Instruction or termMeaning or action
1IdentifyName or pick out the item the question specifies.
2StateExpress the required point directly and clearly.
3DescribeReport the relevant characteristics, events or pattern.
4ExplainConnect the result to its cause, mechanism or reasoning.
5CompareSet the items side by side on the same relevant feature.
6InterpretSay what a statement, result or display means in context.
7JustifyGive evidence for the claim and explain how that evidence supports, qualifies or defends it.
8EvaluateWeigh relevant evidence or criteria before reaching a judgment.
9DetermineWork from the given information to establish an answer.
10CalculateUse numbers or other given information to work out a result.
11EstimateFind an approximate answer using the available clues.
12SketchShow the required shape, relationships and labels.
13ConstructProduce the specified representation using the information given.
14LabelAttach the correct name to the indicated part.
15SelectChoose only the number of options requested.
16CheckTest the answer against the original instruction or condition.
17AnalyzeBreak the information into relevant parts and explain how they relate.
18Multiple-choice questionSelect the answer that satisfies the full stem and any limiting words.
19Free-response questionProduce your own answer and complete each labelled task.
20StimulusUse the figure, extract or other material attached to the question.
21Answer each subpartTreat each lettered instruction as a separate job.
22Hybrid digitalCheck which questions are displayed digitally and which answers go in a paper booklet.

Subject terms and physical models

No.Instruction or termMeaning or action
23Differentiate positionFind instantaneous velocity from the time derivative of position.
24Differentiate velocityFind instantaneous acceleration from the time derivative of velocity.
25Integrate accelerationFind velocity change from the signed time integral.
26Integrate velocityFind displacement from the signed time integral.
27Integrate speedFind total distance from the time integral of velocity magnitude.
28Initial conditionUse the stated starting position or velocity to fix the integration constant.
29Variable forceWrite the force as a function of the relevant coordinate, speed or time.
30Work integralIntegrate the component of force along the displacement path.
31Potential from forceIntegrate the negative of the conservative force component over position.
32Force from potentialTake the negative spatial derivative of potential energy in one dimension.
33Conservative forceIdentify a force whose work between two points does not depend on the path.
34Stable equilibriumIdentify a local minimum of potential energy in the one-dimensional model.
35Unstable equilibriumIdentify a local maximum of potential energy in the one-dimensional model.
36Turning pointFind where kinetic energy vanishes and the direction of motion reverses.
37Instantaneous powerUse the dot product of force and velocity for the power delivered by that force.
38Impulse integralIntegrate net force over the specified time interval.
39Momentum derivativeRelate net external force to the time rate of change of momentum.
40Centre-of-mass velocityDivide total momentum by the system’s total mass.
41Continuous mass distributionRepresent small mass elements using the density and appropriate length, area or volume element.
42Linear mass densityExpress mass per unit length and integrate when density varies.
43Centre-of-mass integralIntegrate position times mass element and divide by total mass.
44Moment-of-inertia integralIntegrate squared distance from the chosen axis over mass.
45Parallel-axis theoremAdd mass times squared axis separation to the centre-of-mass moment of inertia.
46Torque integralSum torques from distributed forces about a specified axis using an integral.
47Angular impulseIntegrate net torque over time to find angular momentum change.
48Angular momentum of a particleTake the cross product of position relative to the origin and linear momentum.
49Work by torqueIntegrate torque about a fixed axis over angular displacement.
50Rolling constraintRelate translation and rotation for motion without slipping.
51Static-friction directionDetermine which relative sliding would occur without friction and oppose that tendency.
52Drag forceModel resistance as a function of speed with direction opposite relative motion through the medium.
53Terminal speedFind the speed where drag balances the other forces along the motion.
54Differential equation of motionTranslate Newton’s law into an equation involving derivatives and solve or analyse it with initial conditions.
55Sinusoidal solutionMatch amplitude, angular frequency and phase to the equation and starting values.
56Angular frequencyUse radians per unit time, equal to 2π divided by the period for periodic motion.
57Small-angle approximationUse sin θ approximately equal to θ in radians when the angle is small.
58Simple pendulum periodUse the small-angle model and identify pendulum length and gravitational acceleration.
59Effective spring constantRelate the net restoring force to displacement near equilibrium.
60Inverse-square gravitationFind gravitational force from masses and inverse squared separation.
61Gravitational potential energyFor two point masses use −GMm/r with zero chosen at infinite separation.
62Circular-orbit speedSet gravitational force equal to the required inward net force for a circular orbit.
63Escape speedSet the minimum energy for reaching infinity with zero remaining speed in the isolated model.
64Orbital periodRelate the orbital circumference and speed for a circular orbit.
65Dimensional check of an integralMultiply the integrand’s units by the integration variable’s units.
66Translate a graph into an integralIdentify the signed area and the physical quantity it represents.
67Compare differential and integral formsState whether the question asks for a local rate or a change over an interval.

Representations, experiments and calculations

No.Instruction or termMeaning or action
68Choose a systemState which objects are included before applying a force, energy or momentum relationship.
69Free-body diagramDraw and label the forces acting on the specified object or system.
70Net forceFind the vector sum of external forces on the selected system.
71Resultant accelerationUse the direction and magnitude of net force per unit mass.
72Inertial reference frameUse a frame in which a force-free object moves at constant velocity.
73DisplacementGive the signed or vector change in position.
74VelocityGive the rate of position change with direction.
75SpeedGive the magnitude of velocity.
76AccelerationGive the rate of velocity change with direction.
77Constant accelerationUse kinematics relationships only where acceleration is constant.
78Position–time graphUse the slope to find velocity at the requested time or interval.
79Velocity–time graphUse slope for acceleration and signed area for displacement.
80Acceleration–time graphUse signed area to find change in velocity.
81Projectile motionTreat horizontal and vertical components separately with a shared time.
82Relative velocityFind velocity with respect to the frame or object named in the question.
83WeightUse the gravitational force on the object, with direction toward the source.
84Normal forceDraw the contact force perpendicular to the supporting surface.
85TensionDraw the pulling force along a taut cord or similar connector.
86Static frictionUse the value needed to prevent sliding up to its maximum.
87Kinetic frictionDraw friction opposite relative sliding at the contact.
88Force pairIdentify equal and opposite interaction forces on different objects.
89Translational equilibriumSet the net force to zero for the system.
90Uniform circular motionTrack changing velocity direction even though speed stays constant.
91Centripetal accelerationFind inward acceleration from speed squared divided by radius.
92Radial directionResolve the quantity along the line from the centre of rotation.
93Tangential directionResolve along the tangent perpendicular to the radial direction.
94WorkFind energy transferred by a force acting through displacement.
95Work–energy theoremRelate total work on an object to its change in kinetic energy.
96Kinetic energyUse one-half mass times speed squared for translational motion.
97Elastic potential energyFor an ideal spring, use one-half spring constant times displacement squared.
98Mechanical energyAdd the kinetic and applicable potential energies of the system.
99Energy transferAccount for energy crossing the system boundary.
100Conservation of energyAccount for energy within the system and transfers across its boundary.
101PowerFind the rate at which energy is transferred or work is done.
102MomentumMultiply mass by velocity and keep track of direction.
103ImpulseUse net force integrated over time, or the momentum change.
104Force–time graphFind impulse from the signed area under the net-force curve.
105Conservation of momentumSet initial and final total momentum equal when net external impulse is negligible.
106Elastic collisionUse conservation of kinetic energy as well as the appropriate momentum condition.
107Inelastic collisionAllow total kinetic energy to change while checking the momentum condition.
108Perfectly inelastic collisionAssign a shared final velocity to objects that stick together.
109Centre of massLocate the mass-weighted average position of the system.
110TorqueUse the lever arm and force to find the turning effect about a chosen axis.
111Lever armFind the perpendicular distance from the axis to the force’s line of action.
112Angular displacementGive the signed change in angle.
113Angular velocityFind the rate of change of angular position.
114Angular accelerationFind the rate of change of angular velocity.
115Rotational inertiaAccount for mass distribution relative to the specified rotation axis.
116Rotational equilibriumSet net torque about the chosen axis to zero.
117Rotational kinetic energyUse one-half rotational inertia times angular speed squared.
118Angular momentumFor a rigid body rotating about a fixed axis, use rotational inertia times angular velocity.
119External torqueIdentify a turning effect produced by an interaction across the system boundary.
120Rolling without slippingRelate centre-of-mass speed to radius times angular speed.
121PeriodFind the time for one complete cycle.
122FrequencyFind the number of cycles per unit time.
123AmplitudeFind the greatest displacement from equilibrium.
124Restoring forceIdentify a force component directed back toward equilibrium.
125Simple harmonic motionCheck that acceleration is proportional to displacement and opposite in direction.
126Spring constantUse the proportionality between force magnitude and displacement for an ideal spring.
127Hydrostatic pressureUse fluid density, gravitational field strength and depth to find the pressure increase.
128Fluid at restUse the hydrostatic pressure relation and buoyancy instead of a flow model.
129Vector componentProject the vector onto the named coordinate axis with the correct sign.
130Sign conventionState which direction is positive and use it consistently.
131Scale drawingUse the requested scale when converting between arrow length and vector magnitude.
132Ranking taskOrder the listed cases and show equal rankings where warranted.
133Translate a representationPreserve the physical relationships when switching between words, equations, diagrams and graphs.
134Linearise dataChoose transformed axes that yield a straight-line relationship for the proposed model.
135Qualitative predictionState how the outcome changes and give a physical reason.
136Quantitative translationUse the mathematical relationship to connect a numerical result with a qualitative claim.
137Experimental design and analysisGive a repeatable method, then explain how its measurements test the relationship.
138Mathematical routineBuild the algebra from a relevant principle and show how it answers the prompt.
139HypothesisState a testable prediction about a relationship.
140Research questionSpecify the focused question that the investigation will answer.
141Independent variableIdentify what the investigator changes deliberately.
142Dependent variableIdentify the measured outcome of the investigation.
143Controlled variableIdentify a factor kept constant to help isolate the tested relationship.
144Control groupUse the baseline comparison to interpret the treatment effect.
145Experimental designUse the stated groups, conditions and measurements to judge the experiment.
146Sample sizeCheck how many observations, individuals or trials contribute to the result.
147Representative sampleCheck whether the selected cases reflect the population of interest.
148Raw dataUse the measurements as originally collected.
149Processed dataUse values calculated, combined or transformed from the original readings.
150OutlierIdentify an observation unusually far from the general pattern.
151UncertaintyState or interpret the estimated doubt associated with a measurement or value.
152Error barsRead their meaning from the figure legend before interpreting them.
153RepeatabilityConsider agreement when the same method is repeated under the same conditions.
154ReproducibilityConsider whether results agree when the method is repeated under changed conditions.
155ValidityConsider whether the evidence or method answers the intended question.
156ReliabilityConsider whether a result or method gives consistent findings.
157Confounding factorIdentify a factor that could contribute to the apparent relationship.
158Operational definitionUse the measurable rule the study gives for the concept.
159CorrelationDescribe how variables vary together within the data.
160CausationExplain how one factor produces a change in another when evidence supports it.
161TrendThe broad direction or pattern over a range.
162PatternA regularity visible across observations or examples.
163ScatterplotDescribe form, direction, strength and unusual points when relevant.
164Line of best fitDraw a line representing the overall pattern of plotted data.
165InterpolateEstimate within the range covered by the data.
166ExtrapolateEstimate outside the observed range using an assumed pattern.
167Read the axesIdentify the quantities, units and intervals on a graph before using a value.
168Gradient from a graphCalculate change in the vertical quantity per change in the horizontal quantity.
169Area under a graphUse the area only where the graph’s quantities make it the requested accumulated value.
170Baseline measurementUse the reading taken before the stated intervention or change.
171Identify the reference groupFind the comparison used to isolate the change attributed to the intervention.
172Explain a limitationIdentify the assumption or data issue that restricts the conclusion.
173Keep the comparison fairCompare quantities on the same stated basis and units.
174Control treatmentUse the treatment intended to provide a reference comparison.
175ResidualSubtract the predicted response from the observed response.
176Significant figuresGive the requested number of meaningful digits.
177Decimal placesCount the required digits to the right of the decimal point.
178Dimensional analysisTrack units through the calculation to see whether the result has the requested dimension.
179Order of magnitudeEstimate the relevant power-of-ten scale.
180Calculate the percentage changeDivide the change by the starting value and multiply by 100.
181Rate of changeFind the change in one quantity per unit change in another.
182Unit rateCalculate the amount corresponding to one unit of the other quantity.
183ParameterUse the fixed or adjustable quantity that defines a family of cases.
184ModelUse a simplified mathematical or conceptual representation to address the task.
185TableInformation arranged in rows and columns.
186GraphA visual display of data or a mathematical relationship.
187DiagramA drawing showing features, structure or relationships.
188ScaleThe intervals or measurement relationship used in a display.
189UnitThe standard attached to a measurement, such as minutes or metres.
190Unit conversionUse a conversion factor to change the units while keeping the quantity the same.
191Interpret the slopeGive the predicted change in response per one unit increase in the explanatory variable.
192Interpret the interceptExplain the predicted response at zero if zero makes sense in context.
193Exact valueLeave the answer in a form that preserves its full value.
194Give unitsAttach the required measurement unit to the final result.
195Find the exact valueRetain radicals, fractions, logarithms or π in exact form where appropriate.
196Set up an equationTranslate the given conditions into a mathematical relationship.
197Check the solutionSubstitute the result into the original equation to verify it.
198In terms ofUse the specified quantity or symbol in the final expression.
199SolveFind the values that satisfy the equation or inequality.
200SubstituteReplace a variable with the given value or expression.

What the AP Physics C: Mechanics exam requires

College Board lists the regular 2027 exam for May 3. The exam is hybrid digital. Answer multiple-choice items in Bluebook and read the free-response prompts there. Handwrite the free responses in the supplied booklet.

Exam componentFormat and weighting
I · Multiple choice42 questions in 85 minutes, worth 50%. Expect standalone items and sets that use shared information.
II · Free response4 questions in 95 minutes, worth 50%. Tasks cover mathematical routines, translation between representations, experimental design and analysis, and translation between qualitative and quantitative descriptions.
Calculator policyBoth sections allow approved four-function, scientific or graphing calculators. Bluebook provides scientific and graphing Desmos calculators.

Use the May 2027 timing when building a mock exam. In graph and experiment tasks, match the diagram or measurement plan to the particular relationship named in the prompt.

AP is a U.S.-based programme taken domestically and internationally. Confirm local reporting time and registration with your school or test centre. Practise with the official materials for your course and exam year.

Read the task before choosing a method

Write the governing principle before substituting. The derivative of position is a local rate, while the integral of velocity over time is a signed displacement. In rotational questions, identify the reference axis before writing a moment of inertia or torque.

Worked examples for common exam instructions

Differentiate to find acceleration

Prompt. For x(t) = 2t³ − 3t in SI units, find the acceleration at t = 2 s.

Answer. Velocity is 6t² − 3. Differentiating again gives acceleration 12t, so the acceleration is +24 m/s².

Integrate a variable force

Prompt. A force F(x) = 4x N acts in the positive x direction as an object moves from 0 to 3 m. Find the work.

Answer. Integrate 4x from 0 to 3. The result is 2x² evaluated at the bounds, or 18 J.

Determine a moment of inertia

Prompt. Set up and evaluate the moment of inertia of a uniform rod of mass M and length L about a perpendicular axis through one end.

Answer. Let x run from 0 to L and use dm = (M/L) dx. Integrating x² dm gives ML²/3.

Design and analyse a spring experiment

Prompt. Describe how to estimate a spring constant from periods measured with different attached masses.

Answer. Measure several oscillations for each mass, then calculate the period. Plot T² versus mass. In the ideal model the slope is 4π²/k, so k is 4π² divided by the fitted slope. Keep oscillations small and use the same spring.

Use the Fencing Method to build an answer

Start with a small, accurate response. Add the detail that fixes it to the question, then add the reason that connects them. Test the explanation on a new case.

Start. Speed increases.

Add context. The velocity and acceleration both point in the positive direction.

Add reasoning. Because the velocity and acceleration have the same sign, acceleration increases the magnitude of velocity.

Transfer. Reverse the velocity while keeping acceleration positive and reassess the speed.

Practise with the 200 terms

Choose one calculation, one graph task and one explanation. Mark where the response identifies the quantity or relationship, provides the requested representation and explains the result. Change one condition and try again.

Distinguish displacement from distance

Try it. Velocity is −2 m/s for 2 s and +3 m/s for 2 s. Find displacement and distance.

Check. Displacement is −4 + 6 = +2 m. Distance is 4 + 6 = 10 m.

Frequently asked questions

What should I show when a prompt says justify?

Give the relevant principle or evidence and connect it to the conclusion. For a direction or sign, state the convention that makes the direction or sign meaningful. Check the scoring guidelines for the specific released question.

Official sources and next reading

College Board AP Physics C: Mechanics exam information and released questions · AP calculator policy · 2027 AP exam schedule

Related AP exam vocabulary guide · eduKateSG vocabulary learning guide · Learn the Fencing Method