Numbers
Edexcel A-Level Physics 9PH0
Working as a Physicist
Topic overviewSI base units, derived units and homogeneityUnit prefixes, conversion and order-of-magnitude estimatesResolution, random errors and systematic errorsUncertainty and how uncertainties combineImproving measurements, graphs and evaluating resultsPeer review, publication and scientific integrityRisk, benefit and the role of science in society
Mechanics
Topic overviewThe equations of uniformly accelerated motionDisplacement-time and velocity-time graphsScalars and vectorsResolving vectors and finding resultantsProjectile motionFree-body diagrams and Newton's first and second lawsNewton's third law, mass and weightTerminal velocity and measuring g by free fallLinear momentum and its conservationElastic and inelastic collisions in one dimensionThe moment of a forceCentre of gravity, equilibrium and the principle of momentsWork done by a forceKinetic and gravitational potential energyConservation of energy and dissipationPower, and the equation P = FvEfficiency and wasted energy
Electric Circuits
Topic overviewCurrent, charge and potential differenceResistance, Ohm's law and ohmic behaviourElectrical power and energyKirchhoff's laws: the current and potential difference rulesCombining resistances in series and parallelCircuit calculations, meters and component failureI-V characteristics of conductors, lamps and diodesThermistors, light dependent resistors and resistance changeResistivity and determining it experimentallyCharge carriers, drift velocity and I = nqvAThe potential divider equation and the loading effectSensing circuits with thermistors and light dependent resistorsElectromotive force, internal resistance and lost voltsMeasuring e.m.f. and internal resistance, and cells in combination
Materials
Topic overviewDensity and how it is measuredUpthrust and Archimedes' principleFloating, sinking and upthrust calculationsViscosity, laminar flow and Stokes' lawTerminal velocity of a sphere falling through a liquidMeasuring viscosity by the falling-ball methodHooke's law, stress and strainThe Young modulus and calculations with itDetermining the Young modulus of a wireForce-extension graphs, elastic and plastic deformationStress-strain graphs, ductile and brittle materialsElastic strain energy
Waves and Particle Nature of Light
Topic overviewDescribing a progressive waveThe wave equation and its useLongitudinal and transverse wavesDisplacement-distance and displacement-time graphsMeasuring the speed of sound with an oscilloscopeWavefronts, superposition and phaseCoherence, path difference and phase differenceInterference in practiceStationary waves, nodes and antinodesHarmonics on a stretched stringInvestigating a vibrating string, and air columnsIntensity, the inverse square law and refractive indexRefraction, wave speed and the critical angleTotal internal reflection and measuring refractive indexLenses, ray diagrams and the images they formLens power and the thin lens equationLens calculations and magnificationReflection, transmission and the pulse-echo principlePulse-echo calculations, resolution and ultrasoundPolarisation and diffractionSingle-slit patterns and the diffraction grating equationGrating spectra and measuring wavelengthElectron diffraction and the de Broglie equationde Broglie calculations and wave-particle dualityPhotons and photon energyModels of light and the electronvoltLine spectra and atomic energy levelsThe photoelectric effect and Einstein's equationEvidence for the photon model and photoelectric calculations
Further Mechanics
Topic overviewImpulse and force-time graphsConservation of momentum in two dimensionsInvestigating momentum and analysing collisions on videoElastic and inelastic collisionsKinetic energy, momentum and collision calculationsThe radian, angular displacement and angular velocityAngular velocity, period and frequency of rotationCentripetal accelerationCentripetal force and what provides itVertical loops and centripetal force calculations
Electric and Magnetic Fields
Topic overviewElectric fields and electric field strengthField strength calculations and field diagramsCoulomb's law and the field of a point chargeInverse-square behaviour and combining fieldsElectric potential and field strength as a potential gradientUniform fields between parallel plates, and the potential near a point chargeEquipotentials, field diagrams and work doneCapacitance and the energy stored in a capacitorCapacitor charge and energy calculationsCharging and discharging graphs and the time constantThe exponential decay equations and logarithmic graphsInvestigating capacitor discharge and time-constant calculationsMagnetic flux density, flux and flux linkageForces on currents and moving chargesThe conditions for inducing an e.m.f.Faraday's law and Lenz's lawFlux linkage graphs and induced e.m.f. calculationsAlternating current, peak and r.m.s. valuesOscilloscope traces and alternating current calculations
Nuclear and Particle Physics
Topic overviewNuclide notation, isotopes and the alpha scattering experimentConclusions from alpha scattering and the changing model of the atomThermionic emission and linear acceleratorsThe cyclotron and the radius of a charged particle's pathParticle tracks, conservation laws and why high energies are neededMass-energy equivalence, pair production and annihilationParticle energy units and relativistic lifetimesBaryons, mesons, leptons and quark compositionThe six quarks, antiparticles and fundamental particlesConservation of charge, baryon number and lepton numberQuark changes in beta decay and testing particle equations
Thermodynamics
Topic overviewSpecific heat capacity and specific latent heatMeasuring specific heat capacity and calibrating a thermistorMeasuring specific latent heatInternal energy, temperature and absolute zeroMean kinetic energy and the absolute temperature scaleThe kinetic theory equation and its derivationThe ideal gas equation and molecular kinetic energyBoyle's law and investigating a fixed mass of gasBlack body radiation and Wien's lawThe Stefan-Boltzmann law and stellar calculations
Space
Nuclear Radiation
Topic overviewMass deficit, binding energy and the atomic mass unitBinding energy per nucleon, fission and fusionBackground radiation and the three types of nuclear radiationIonising power, penetration and changes in the nucleusNuclear equations and investigating gamma absorptionActivity, the decay constant and half-lifeDecay graphs and half-life calculations
Gravitational Fields
Oscillations
Topic overviewThe conditions for simple harmonic motionDisplacement, velocity and acceleration in simple harmonic motionThe mass-spring oscillator and the simple pendulumDisplacement, velocity and acceleration graphsReading period, amplitude and speed from oscillation graphsEnergy in an undamped oscillationDamping and where the energy goesFree and forced oscillations and resonanceResonance in practice and determining an unknown mass
Further Mechanics
- 10 subtopics
- 15 things to know
- Papers 1 and 3
What Further Mechanics covers
Paper 1 content that extends momentum into two dimensions and introduces circular motion: impulse and force-time graphs, elastic and inelastic collisions, the radian and angular velocity, and centripetal acceleration and force.
Where it is assessed
Papers 1 and 3
Advanced Physics I, then the general and practical principles paper.
Check the Pearson Edexcel specification ↗The 10 subtopics
Each one has its own page.
- Impulse and force-time graphsRecall questions on impulse and why it shares momentum's unit, Newton's second law in momentum form, the area under a force-time graph, and why a crumple zone reduces force.Open →
- Conservation of momentum in two dimensionsRecall questions on resolving momenta into components, why magnitudes cannot simply be added, and applying conservation to an explosion or a glancing collision.Open →
- Investigating momentum and analysing collisions on videoRecall questions on the core practical linking force to change of momentum, the graph and its gradient, the systematic error, and video analysis of colliding spheres.Open →
- Elastic and inelastic collisionsRecall questions on the definitions, the calculation that distinguishes them, where the missing kinetic energy goes, and whether a collision can lose all of it.Open →
- Kinetic energy, momentum and collision calculationsRecall questions on the derivation of Eₖ = p²/(2m) and its limits, comparing particles of equal energy or equal momentum, and the relative speeds in an elastic collision.Open →
- The radian, angular displacement and angular velocityRecall questions on the definition of the radian, converting between degrees and radians, the arc-length relationship, and the definitions of angular displacement and velocity.Open →
- Angular velocity, period and frequency of rotationRecall questions on v = ωr, the relationships between angular velocity, period and frequency, and comparing two points at different radii on one disc.Open →
- Centripetal accelerationRecall questions on why circular motion at constant speed is accelerated, the direction of the acceleration, the two equations, and how each responds to a change of speed or radius.Open →
- Centripetal force and what provides itRecall questions on why a resultant force is needed, why centripetal force is not an extra force, why it does no work, and what supplies it for a car and a satellite.Open →
- Vertical loops and centripetal force calculationsRecall questions on the forces at the top and bottom of a vertical loop, the minimum speed condition, and what happens when the centripetal force is removed.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Evaluation
Why is momentum still conserved in a real collision between ball bearings, and what systematic error affects the practical?
Key term
What does conservation of linear momentum state, and why can momenta in two dimensions not simply be added as magnitudes?
Numbers
What is an example of a nearly perfectly elastic collision, and can a collision lose all of its kinetic energy?
Process
What calculation decides whether a collision is elastic or inelastic, and what happens in a perfectly inelastic one?
Numbers
What is always true of the relative speeds in an elastic collision, what happens when a moving ball collides elastically and head-on with an identical stationary ball, and what happens to kinetic energy when momentum doubles?
Key term
A ball dropped onto a floor rebounds to a lower height than it fell from. What does this tell you about the collision, and why?
Numbers
What is the relationship between arc length, radius and angle, and why must the angle be in radians?
Numbers
What are angular displacement and angular velocity, and what is the unit of angular velocity?
Numbers
How is angular velocity related to the period and to the frequency of rotation, and how do the angular velocities of two points at different radii on a rotating disc compare?
Process
How do you convert a number of complete revolutions into an angular displacement in radians?
Numbers
Why is an object moving in a circle at constant speed accelerating, in which direction, and what happens if its speed doubles?
Numbers
What provides the centripetal force for a car turning on a level road, and what happens if the radius doubles at constant speed?
Key term
Why do passengers feel thrown outwards when a vehicle turns a sharp corner?
Key term
A vehicle rounds a banked track at exactly the design speed with no sideways friction. Which forces act, and what conditions apply?
Take Further Mechanics further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Angular velocity vs Linear velocity
Angular velocity: angle swept per unit time. Linear velocity: displacement travelled per unit time.
Centripetal force vs Centrifugal force
Centripetal force: resultant interaction directed towards the centre. Centrifugal force: apparent outward effect in a rotating frame.
Elastic collision vs Inelastic collision
Elastic collision: total kinetic energy is conserved. Inelastic collision: total kinetic energy is not conserved.
Questions from this topic
Each one with the model answer underneath.
- 1
What is the linear momentum of a body, and what kind of quantity is it?
Model answer
Momentum is the product of a body's mass and its velocity, p = mv, and it is a vector quantity acting in the direction of the velocity.
- 2
State the SI unit of momentum and the equivalent unit used for impulse:
Model answer
Momentum is measured in kg m s⁻¹, which is identical to the newton second, N s.
- 3
How is Newton's second law stated in terms of momentum?
Model answer
The resultant force acting on a body equals its rate of change of momentum, F = Δp/Δt.
- 4
What is meant by the impulse of a force?
Model answer
Impulse is the product of a force and the time for which it acts, FΔt, and it equals the change of momentum it produces.
- 5
Why do impulse and momentum share the same unit?
Model answer
Impulse is equal to the change of momentum, so N s and kg m s⁻¹ must reduce to the same combination of base units.
- 6
What physical quantity is represented by the area under a force–time graph?
Model answer
The area represents the impulse delivered, which is equal to the change of momentum of the body.
What is inside Levo
Six ways to work the same material.
Further Mechanics revision questions
- What does Further Mechanics cover in Edexcel A-Level Physics?
- 10 subtopics: impulse and force-time graphs, conservation of momentum in two dimensions, investigating momentum and analysing collisions on video, elastic and inelastic collisions, kinetic energy, momentum and collision calculations, the radian, angular displacement and angular velocity, angular velocity, period and frequency of rotation, centripetal acceleration, centripetal force and what provides it and vertical loops and centripetal force calculations. Each one has its own page with questions and model answers.
- How is Further Mechanics organised?
- By the Edexcel 9PH0 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Further Mechanics, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
Or £46 a year, about £3.83 a month. Cancel anytime.