UNSW Sydney · FACULTY OF PHYSICS

DPST1021 Physics 1A

- one subject, every graph, every model, every mark

15 Chapters67-page Bible

Our own words - no uploaded lecturer files

Updated for this semester

The Complete Exam Bible · T3 2026

DPST1021 Overview

Physics 1A

— Worked DPST1021 problems for UNSW College Physics 1A: kinematics, forces, energy, momentum, rotation, gravitation, thermal physics, oscillations, waves and sound.

UNSW College
Term 3, 2026
Level 1 (Diploma)
6 units of credit

DPST1021 Physics 1A is a first-year, calculus-based physics course taught by UNSW College on the UNSW Sydney campus for students in the Diploma of Science, Diploma of Engineering and Diploma of Computer Science pathways.

Pass hurdles Tutorial Performance 20/20, labs 6.5/8, and at least 50% in each test, with 80% attendance expected.
Test material Questions are drawn from the ten homework quizzes.
Formula sheet Supplied in both tests, so practise choosing the right line.
Lab habit Pass each pre-lab quiz and carry uncertainties through every result.

DPST1021 · UNSW Sydney

An independent, AskSia-authored study guide. AskSia is not affiliated with, endorsed by, or sponsored by UNSW Sydney; the course code and name are used for identification only.

Assessment

How DPST1021 is assessed

Component	Weight	Format
Mid-session tests (2)	20%	2026 UNSW Handbook: theory tests on problem-solving and understanding of concepts, 10% each.
Quizzes & Class Performance	10%	2026 UNSW Handbook: short computer-generated quizzes plus classroom performance.
Final examination	50%	2026 UNSW Handbook: theory test on problem-solving and understanding of core concepts.
Laboratory Component	20%	2026 UNSW Handbook: online pre-lab testing plus marks for experimental work and related questions.
Tutorial Performance · hurdle		Term 3, 2026 outline hurdle: 20 out of 20, one point for each sensible attempt at the set tutorial problem from Week 2.
Laboratory Work · hurdle		Term 3, 2026 outline hurdle: at least 6.5 out of 8 across eight labs, each scored Pass 1, Borderline 0.5 or Fail 0.
Test 1 · hurdle		Term 3, 2026 outline hurdle: at least 50%. Mechanics, lectures 1 to 17; 40 minutes, 10 marks, up to three attempts.
Test 2 · hurdle		Term 3, 2026 outline hurdle: at least 50%. Thermal physics and waves, lectures 18 to 32; 40 minutes, 10 marks, up to three attempts.

Two schedules are published for this course and they are alternatives, not extra tasks to add together. The first four rows come from the 2026 UNSW Handbook, whose weights total 100%. The Term 3, 2026 course outline, which is the document written for this term, says the course will not be graded and that your report shows only SY or FL. To pass under that outline you need all four hurdle rows: 20 out of 20 for Tutorial Performance, at least 6.5 out of 8 for Laboratory Work, and at least 50% in Test 1 and in Test 2. Each test has up to three attempts. The outline also expects you to attend at least 80% of classes and recommends full attendance. A lab counts as a Fail for the week unless its pre-lab quiz scores 50% or more. Ask your convenor on Moodle if you are unsure which schedule governs your enrolment.

Two published schedules. Left: the Handbook weights, which total 100%. Right: the four hurdles in the Term 3, 2026 outline, all of which must be met for an SY result.

Current dates · verify in LMS

Current DPST1021 dates

Date	Item	Control
19 October 2026	Test 1, attempt 1	Week 8, during the laboratory class; attempts 2 and 3 run in workshop time in Weeks 8 and 9.
Week 14, from 30 November 2026	Test 2, attempts 1 to 3	Set on the end-of-term timetable; the course schedule leaves the exact date to be announced.
16 November 2026	Lab 8: Standing Waves in a Tube	Week 12, the last of the eight laboratory sessions.

Dates are as published in the Term 3, 2026 course outline and course schedule. Confirm exact deadlines and submission settings in the live LMS.

Contents · every chapter, one map

What DPST1021 covers

DPST1021 moves through three blocks in lecture order. Mechanics comes first and is the content of Test 1; thermal physics and waves follow and are the content of Test 2. A final chapter covers the measurement and graphing skills that every laboratory uses.

Kinematics, Vectors and Motion Graphs

Scalars and vectors, unit-vector notation, average and instantaneous velocity, motion graphs and constant-acceleration equations

The first two lectures of Physics 1A set up the language that the whole mechanics block depends on.

Scalars and vectors: sort quantities by whether direction matters, and list familiar examples of each such as mass and time against displacement and force.
Unit-vector notation: write a vector as components along i, j and k, add vectors component by component and find a magnitude with Pythagoras.
Direction angles: convert components to an angle and correct the calculator result using the signs of the components to find the right quadrant.
Average versus instantaneous: divide displacement by elapsed time for an average velocity, and differentiate the position function for the value at one instant.
Motion graphs: read velocity as the gradient of a position-time graph and displacement as the signed area under a velocity-time graph.
Constant acceleration and free fall: apply the four kinematic equations with g = 9.80 m/s squared and a fixed sign convention, keeping the physically meaningful root.

Projectile Motion and Relative Velocity

Independent horizontal and vertical motion, launch-angle problems and velocity measured from a moving frame

Lecture 3 of Physics 1A takes the straight-line kinematics of the first week and lets it run in two or three dimensions.

Vector kinematics: write position, velocity and acceleration as vectors in i, j and k, and apply each constant-acceleration equation to one axis at a time.
Launch components: resolve an initial speed and angle into horizontal and vertical parts using cosine and sine, keeping the sign of each part.
Independent axes: treat horizontal motion as constant velocity and vertical motion as free fall with g = 9.80 m/s squared, sharing only the elapsed time.
Unequal heights: solve the vertical quadratic for the flight time when launch and landing heights differ, and keep only the root that makes physical sense.
Impact velocity: rebuild the final speed and direction from the two components, and confirm the speed with an energy check where possible.
Relative velocity: derive the velocity of A relative to B from the difference of position vectors, then subtract velocities to solve wind, current and rain problems.

Newton's Laws and Uniform Circular Motion

Free body diagrams, the three laws, tension and normal forces, Hooke's law, centripetal acceleration and banked turns

Week 2 of Physics 1A moves from describing motion to explaining it.

Circular motion quantities: link period, angular speed, speed and radius through v = rω and v = 2πr/T, then find the centripetal acceleration.
Average and instantaneous acceleration: separate the change in velocity over an interval from the centre-pointing value at a single point on the circle.
Free body diagrams: isolate one body and draw its weight, every tension and every normal force acting on it.
First law and inertial frames: recognise constant velocity as the zero-net-force state and identify accelerating frames where the law appears to fail.
Third law and internal forces: pair forces acting on different bodies, and choose systems so internal pairs cancel.
Hooke's law: model a spring force as proportional and opposite to the extension, then combine it with the second law.

Friction, Inclined Planes and Drag

Static and kinetic friction coefficients, forces on slopes, connected bodies and terminal speed

Week 3 of Physics 1A opens with Lecture 7 on friction and inclined surfaces, then starts Lecture 8 with the drag force. Together they extend Newton's laws from idealised smooth surfaces to the contact forces that real objects feel.

Static friction: a force that takes any value up to the product of the static coefficient and the normal force, found from the force balance whenever nothing slips.
Kinetic friction: a constant resisting force equal to the kinetic coefficient times the normal force, acting opposite to the sliding velocity once motion has begun.
Normal force on a ramp: the perpendicular contact force, equal to mg cos theta only when no other force pushes into or lifts away from the slope.
Slip angle on a ramp: the steepest tilt at which a block can stay at rest, where the tangent of the angle equals the static coefficient.
Sliding on an incline: the downhill acceleration g(sin theta minus the kinetic coefficient times cos theta), which reduces to zero for constant-velocity sliding.
Drag and terminal speed: a speed-dependent air resistance that grows until it matches the weight, giving a steady maximum speed for a falling body.

Work, Energy and Power

Work as a dot product, variable forces, the work-energy theorem, potential energy, conservative forces and power

Lectures 8 to 10 shift the mechanics block from forces to energy.

Energy of motion: kinetic energy, one half m v squared, a scalar in joules that ignores direction.
Work by a constant force: the dot product of force and displacement, positive when the force helps the motion and zero when it acts at right angles.
Work-energy theorem: the statement that the net work done by all forces on a body equals the change in its kinetic energy over the same interval.
Variable forces: work found by integrating force over position or measuring the area under a force-position graph, with the Hooke's-law spring as the standard case.
Potential energy: stored energy defined for conservative forces such as gravity and springs, related to force by F equals minus dU/dx.
Conservation and power: mechanical energy stays constant when only conservative forces do work, while power measures the rate at which work is done, in watts.

Centre of Mass, Momentum and Collisions

Centre of mass of systems, momentum and impulse, conservation in one and two dimensions, elastic and inelastic collisions

Lectures 11 to 13 of Physics 1A move from single bodies to systems. Weeks 4 and 5 of the term introduce the centre of mass of particle collections and extended objects, then build linear momentum, impulse and collisions on top of it.

Composite-shape centres of mass: split an object into symmetric pieces, place each piece's mass at its own centre, and form the mass-weighted average position.
System momentum: add the momenta of all parts, equate the total to M times the centre-of-mass velocity, and let only external forces change it.
Conservation conditions: choose a system boundary that makes contact forces internal, and justify that outside impulse is negligible during a brief collision.
Impulse and average force: link the change in momentum to the area under a force-time curve and explain why longer contact times reduce peak forces.
Collision classification: compare kinetic energy before and after to label a collision elastic, inelastic, perfectly inelastic or explosive.
Two-dimensional collisions: resolve every velocity into components and solve one momentum equation for each axis before recombining magnitude and direction.

Rotation, Torque and Angular Momentum

Angular kinematics, moment of inertia, torque as a cross product, rolling energy and conservation of angular momentum

Rotation closes the Newtonian mechanics block of Physics 1A, just before gravitation.

Rotational analogues: pair angle, angular velocity, angular acceleration, inertia, torque and angular momentum with their translational partners and convert results between them.
Constant angular acceleration: apply the rotational versions of the kinematics equations, working in radians, and convert to revolutions only at the end.
Axis-dependent inertia: compute I from the particle sum or the integral of r squared dm, and explain why it changes when the axis moves.
Torque and rotational dynamics: evaluate torque as a cross product, find its direction with the right-hand rule, and solve problems with net torque equal to I alpha.
Rolling and rotational energy: split kinetic energy into translational and rotational shares using v equal to R omega, and compare speeds of different shapes.
Angular momentum: use L equal to I omega for rigid bodies and conserve it whenever the net external torque about the axis is zero.

Gravitation, Satellites and Orbits

Newton's law of gravitation, variation of g, gravitational potential energy and the energy of circular orbits

Gravitation closes the mechanics block of Physics 1A.

Newton’s law of gravitation: calculate the attractive force between two masses from G, the product of the masses and the inverse square of their separation.
Field strength and altitude: express g as GM/r squared outside a sphere, with r measured from the centre, and predict how it changes with height.
Rotation and shape effects: account for the centripetal share of gravity at the equator and explain why measured g differs between locations on Earth.
Superposition of attractions: add forces from two or more bodies as vectors, and locate points where competing attractions cancel along a line.
Potential energy on large scales: apply U equals minus Gm1m2 over r, take differences between two radii, and recognise when mgh is an acceptable shortcut.
Energy of circular orbits: derive orbital speed from the centripetal condition and relate kinetic, potential and total energy at any orbital radius.

Temperature, Calorimetry and Heat Transfer

The zeroth law, thermal expansion, specific and latent heat, conduction and radiation rates

Thermal physics begins in week 8, and this material opens the content for Test 2. It starts with the zeroth law of thermodynamics, the statement that makes temperature a measurable shared property, and then defines the kelvin scale through absolute zero.

Zeroth law and temperature: explain how equilibrium with a third body defines temperature and makes a thermometer reading meaningful.
Kelvin scale and absolute zero: convert between Celsius and kelvin, and identify the formulas where absolute temperature must be used.
Thermal expansion: calculate changes in length, area and volume from data-sheet coefficients, including holes in plates and liquids in containers.
Specific heat and calorimetry: write an energy balance for an insulated mixture and solve for an unknown temperature or specific heat.
Latent heat and phase changes: decide whether melting or boiling completes before writing the balance, and read heating curves with flat plateaus.
Nucleation: describe how impurities and rough surfaces help bubbles and crystals form, and give examples of superheating.

Kinetic Theory and the Ideal Gas Law

Pressure from molecular impacts, PV = nRT, temperature as average kinetic energy, degrees of freedom and equipartition

Lectures 20 and 21 open the gas part of the thermal physics block, arriving in week 8 straight after temperature, specific heat and latent heat. The material links two views of a gas.

Pressure from collisions: treat each impact as a normal momentum transfer of 2mv and relate the average force on a wall to pressure through P = F/A.
Ideal gas law: apply PV = nRT with moles or PV = NkT with molecules, always using absolute pressure, cubic metres and kelvin.
Kinetic temperature: connect the average translational kinetic energy of one molecule to temperature through three halves of kT, and find rms speeds from it.
Degrees of freedom: count f = 3 for monatomic gases and f = 3, 5 or 7 for diatomic gases according to the temperature ranges on the formula sheet.
Equipartition and internal energy: give each active degree of freedom half of kT per molecule and compute internal energy or its change for n moles.
Speed distribution and mean free path: describe how the spread of speeds shifts with temperature and how collision spacing depends on density and molecular size.

The First Law and Thermodynamic Processes

Internal energy, heat and work on a gas, PV diagrams, molar specific heats and the four standard processes

Lectures 22 and 23, taught in week 9, turn the kinetic picture of a gas into a working accounting system for energy. Internal energy is stored in molecular motion, and it changes only when heat crosses the boundary or work is done on the gas.

First law with course signs: write ΔEint = Q + W with W done on the gas, and convert textbook equations written with work done by it.
Work as area: compute W = −∫P dV from a PV diagram, using rectangles, trapezia or a logarithm, with the correct sign.
Path dependence: explain why Q and W differ between routes joining two states while ΔEint depends only on the temperatures at the ends.
Molar heat capacities: derive CV = fR/2 and CP = CV + R, and infer degrees of freedom from measured heat capacities.
Four standard processes: state what isobaric, isovolumetric, isothermal and adiabatic changes hold fixed and write Q, W and ΔEint for each.
Adiabatic curves and engines: apply PVγ = constant to rapid compressions and expansions, such as the strokes of a combustion engine.

Simple Harmonic Motion and Pendulums

The SHM equation, period and angular frequency, energy in oscillation, the link to circular motion and pendulum periods

Oscillations open the waves block of Physics 1A in week 10, across Lectures 25 and 26. The starting point is a precise definition: a body performs simple harmonic motion when the net force on it is proportional to its displacement from equilibrium and directed back toward it.

Definition of SHM: identify a restoring force proportional to displacement and opposite in direction, then write the acceleration as minus omega squared times x.
Spring oscillator relations: connect omega, frequency and period with the square root of k over m, and see why the period ignores amplitude.
Energy exchange: track kinetic and elastic energy through a cycle with a constant total of half k A squared, and find speed at any displacement.
Reference circle: treat SHM as the projection of uniform circular motion and use it to choose the phase constant from initial conditions.
Pendulum periods: apply small-angle results for simple, physical and torsion pendulums, using the moment of inertia about the pivot for rigid bodies.
Damping and driving: describe the decaying amplitude of a damped system and the large response near resonance, without calculation.

Travelling Waves, Superposition and Standing Waves

The harmonic wave function, wave speed on a string, transmitted power, interference and harmonics on a string

Week 11 of Physics 1A moves from a single oscillator to a disturbance that travels.

Wave types: distinguish transverse from longitudinal motion of the medium and give an everyday example of each, such as a string and sound in air.
Wave function terms: read amplitude, wave number, angular frequency and phase constant from y(x, t), and convert them to wavelength, frequency and speed.
Direction and particle motion: decide the travel direction from the sign between kx and omega t, and find the peak transverse speed as omega A.
String speed and power: calculate speed from tension and linear density, then the transmitted power, noting its dependence on amplitude squared and omega squared.
Boundaries: sketch reflected and transmitted pulses at fixed ends, free ends and joins between light and heavy strings, keeping frequency unchanged across the join.
Superposition and phase: add two equal waves differing in phase to get amplitude 2A cos(phi/2), with constructive and destructive limits.

Sound Waves, the Doppler Effect and Beats

Pressure and displacement amplitude, intensity and sound level, the Doppler equation, shock waves, air columns and beats

Week 12 closes the waves block of Physics 1A with three lectures on sound, the last material assessed in Test 2. Lecture 30 treats sound as a longitudinal travelling wave in a gas.

Longitudinal sound waves: describe how compressions and rarefactions form and write a harmonic displacement function for the air.
Pressure and displacement amplitudes: convert between them using air density, wave speed and angular frequency, noting their quarter-cycle offset.
Intensity and decibels: find intensity from power and distance for a point source, then express it as a sound level.
Doppler shifts: choose numerator and denominator signs for a moving listener and a moving source, including problems with wind.
Shock cones and Mach number: relate the cone half-angle behind a supersonic object to the ratio of the two speeds.
Resonant pipes and beats: list allowed harmonics for open and closed pipes with end corrections, and find beat rates from two frequencies.

Measurement, Uncertainty and Straight-Line Graphs

Absolute and relative uncertainty, combining uncertainties, lines of worst fit and extracting a constant from a gradient

Physics 1A treats laboratory work as a core strand, not an add-on.

Absolute and relative uncertainty: report a measurement as a value plus a range in its own units, or as a fraction or percentage of the value.
Single readings: take the stated instrument accuracy where one is given, otherwise use half of the smallest graduation on the scale.
Repeated trials: use the standard deviation for a large set and half the range for fewer than about ten trials.
Propagation rules: combine absolute uncertainties for sums and relative ones for products, switching to quadrature when the quantities are independent.
Linearising a law: rearrange an equation into Y = AX + B so the plotted graph is straight and the wanted constant sits inside the gradient.
Worst-fit lines: draw the steepest and shallowest lines through the error bars and quote half their difference as the gradient uncertainty.

It is worth 6 units of credit, sits at Level 1 (Diploma), and assumes Year 12 Physics, with Mathematics 1A (DPST1013) or Fundamentals of Mathematics B (DPST1012) taken alongside it. The course is run together with Higher Physics 1A (DPST1023) on one shared schedule, and the course is examined at two levels, with DPST1021 the lower one.

The Term 3, 2026 syllabus has three blocks.

Mechanics runs from vectors and motion in one, two and three dimensions through Newton's laws, friction, work and energy, centre of mass and momentum, rotation and torque, to gravitation and orbits. Thermal physics covers temperature and thermal expansion, specific and latent heat, the kinetic theory of the ideal gas, the first law of thermodynamics with PV diagrams, and heat transfer by conduction and radiation.

Waves covers simple harmonic motion and pendulums, travelling and standing waves, sound, sound levels and the Doppler effect. Each week has three lectures, two tutorials and a problem-solving workshop, and eight weeks add a two-hour laboratory. The College expects you to attend at least 80% of classes.

Assessment is where this course needs care, because two published descriptions disagree.

The 2026 UNSW Handbook lists weighted components totalling 100%, including a 50% final examination.

The Term 3, 2026 course outline and the Moodle assessment table describe the course as ungraded: you pass by meeting four hurdles, namely 20 out of 20 for Tutorial Performance, at least 6.5 out of 8 for Laboratory Work, and at least 50% in each of Test 1 and Test 2. Both tests give you up to three attempts, provide the Formulae and Data Sheet, and draw their questions from the ten homework quizzes.

This guide follows the order of the lectures, works every method with numbers you can check, and points to the formula-sheet line that each problem needs.

Worked example · free

Speed at the bottom of a rough ramp, by energy and by force

Q [6 marks]. Original AskSia exercise: a 2.0 kg box is released from rest at the top of a ramp 3.0 m long, inclined at 30° to the horizontal. The coefficient of kinetic friction is 0.20. Take g = 9.80 m/s², the value on the course data sheet. Find the speed of the box at the bottom, then confirm it with Newton's second law. AskSia practice weighting: 6 marks; this is not a university marking scheme.

Tilted axes. With x along the slope, the weight splits into mg sinθ acting down the incline and mg cosθ pressing it into the surface. Static friction f balances the first; the normal force N balances the second.

1Normal force: N = mg cos 30° = 2.0 × 9.80 × 0.866 = 16.97 N, so kinetic friction is f = μN = 0.20 × 16.97 = 3.39 N, directed up the slope.
1Height lost: h = 3.0 sin 30° = 1.50 m, so gravity does work mgh = 2.0 × 9.80 × 1.50 = 29.4 J on the box.
1Friction does work −f d = −3.39 × 3.0 = −10.2 J. The normal force is perpendicular to the motion and does no work.
2Work-energy theorem: K = 29.4 − 10.2 = 19.2 J, so v = √(2K/m) = √(2 × 19.2 / 2.0) = 4.38 m/s.
1Check by force: a = g sin 30° − μg cos 30° = 4.90 − 1.70 = 3.20 m/s², and v² = 2ad = 2 × 3.20 × 3.0 = 19.2, so v = 4.38 m/s again.

The box reaches the bottom at about 4.4 m/s. The energy route and the force route agree because both use the same friction force; the energy route avoids resolving acceleration but must count friction as negative work. Quoted to two significant figures, matching the least precise data, the answer is 4.4 m/s.

Sia tip — Friction on a slope is μmg cosθ, not μmg: multiply by the cosine before you find the work it does, and give that work a negative sign because the force opposes the motion.

Glossary

Key terms

Displacement: The vector change in position between a start point and an end point. Unlike distance, it depends only on where the motion begins and ends.
Free body diagram: A sketch of one object showing every external force on it as an arrow from that object. It is the starting point for applying Newton's second law.
Coefficient of kinetic friction: The ratio of the kinetic friction force to the normal force for surfaces sliding over each other, written μ_k.
Work-energy theorem: The statement that the net work done on a body equals the change in its kinetic energy.
Impulse: The time integral of a force, equal to the change in momentum it produces.
Moment of inertia: The rotational counterpart of mass, Σm r² for particles, which sets how hard a body is to spin up about a given axis.
Ideal gas law: The equation of state PV = nRT linking the pressure, volume, amount and absolute temperature of an ideal gas.
Internal energy: The total microscopic kinetic and potential energy of a system's particles, written E_int.
Simple harmonic motion: Oscillation in which acceleration is proportional to displacement and directed back toward equilibrium.
Sound level: A logarithmic measure of intensity in decibels, β = 10 log₁₀(I/I₀).

FAQ

DPST1021 FAQ

What do I need to pass Physics 1A at UNSW College?

The Term 3, 2026 course outline sets four hurdles: 20 out of 20 for Tutorial Performance, at least 6.5 out of 8 for Laboratory Work, and at least 50% in each of Test 1 and Test 2. It reports only SY or FL, and also expects at least 80% class attendance. The 2026 UNSW Handbook publishes a weighted schedule instead, so check with your convenor which governs your enrolment.

What is allowed during Test 1 and Test 2?

Each test runs for 40 minutes under invigilated conditions on your own laptop in the SchoolYear Safe Exam Workspace. You receive the Formulae and Data Sheet and blank working paper, and calculators must come from the UNSW approved list. No other reference material is permitted, and generative AI cannot be used.

How are the tests connected to the homework quizzes?

The outline says test questions are taken from the online homework quizzes: quizzes 1 to 5 feed Test 1 and quizzes 6 to 10 feed Test 2. The quizzes carry no marks but can be repeated, so working through every version of each question is the most direct preparation the course offers.

Why was my quiz answer marked wrong when the number looked right?

Many STACK quiz questions check significant figures. The course rule is to give the number of significant figures common to all the values used in the calculation. Too many or too few figures can be marked incorrect even when the physics is sound, so round deliberately at the last step.

What happens if I fail a lab or miss one?

Each lab is scored 1, 0.5 or 0, and you need 6.5 out of 8. A lab is a Fail for that week unless its pre-lab quiz reaches 50%. Once per term you can swap to an individual catch-up lab by submitting the Moodle form before 11 pm on the day you missed; catch-up labs need 70% to pass.

Is Physics 1A different from Higher Physics 1A?

They follow one course schedule and the same three topic blocks, but the course is examined at two levels: DPST1021 is the lower level and DPST1023 the higher. The higher course adds a fifth learning outcome on modelling non-uniform objects, and its homework problems are set separately.

Which textbook should I use?

The official text is Fundamentals of Physics (Extended) by Halliday, Resnick and Walker, 10th edition, and earlier editions are described as nearly as good. The free OpenStax University Physics volumes are listed as another reference, and the weekly WebStream lessons link to matching sections.

Chapter questions

Questions students ask in each DPST1021 chapter

Can an object have zero velocity but a non-zero acceleration?: Yes. A ball thrown straight up is momentarily at rest at the top of its flight, yet gravity is still changing its velocity at 9.80 m/s squared downward. Velocity says how fast position is changing; acceleration says how fast velocity is changing, and the two are independent at any single instant. Chapter 01 · Kinematics, Vectors and Motion Graphs
Why does the horizontal velocity of a projectile stay constant?: Once air resistance is ignored, the only force is gravity, and gravity acts straight down. Nothing pushes or pulls sideways, so the horizontal acceleration is zero and the horizontal component keeps its launch value until landing. Real objects slow a little because drag acts against the whole velocity. Chapter 02 · Projectile Motion and Relative Velocity
Is centripetal force a separate force to draw on a diagram?: No. Centripetal describes a direction, not a source. On a free body diagram you draw only real forces such as tension, weight, normal force or friction; the centripetal force is the net component of those forces that points to the centre. An extra arrow labelled centripetal counts that push twice. Chapter 03 · Newton's Laws and Uniform Circular Motion
Does a heavier block slide down a ramp more easily?: Not in the simple friction model. Both the downhill weight component and the maximum friction are proportional to mass, so mass cancels from the condition for slipping and from the sliding acceleration. A heavy and a light block made of the same material start to slip at the same tilt and speed up at the same rate once moving. Chapter 04 · Friction, Inclined Planes and Drag
Can work be negative?: Yes. Work is negative when the force has a component opposite to the displacement, so it takes kinetic energy away. Friction on a sliding block, gravity on a rising ball and a brake on a moving car all do negative work. A negative value is a direction of energy flow, not an error. Chapter 05 · Work, Energy and Power
Can momentum be conserved while kinetic energy is not?: Yes, and in everyday collisions it is the usual case. Momentum depends only on external forces, which are negligible during a short impact. Kinetic energy has no such protection, since deformation, sound and heating absorb part of it. A car crash conserves momentum almost exactly yet turns much of its kinetic energy into bent panels. Chapter 06 · Centre of Mass, Momentum and Collisions
Why must angles be in radians for rotational formulas?: The link between arc length and angle, s equals r theta, only holds when theta is measured in radians, because the radian is defined as arc length divided by radius. Relations such as v equals r omega and tangential acceleration equals r alpha inherit that definition, so degrees or revolutions give answers off by constant factors. Chapter 07 · Rotation, Torque and Angular Momentum
Why is gravitational potential energy negative?: Zero is chosen at infinite separation, and gravity is attractive, so bringing masses closer releases energy and leaves U below zero. Only differences matter in a calculation. A satellite with negative total energy is bound and would need extra energy to reach zero before escaping. Chapter 08 · Gravitation, Satellites and Orbits
Why does water stay at 100 degrees Celsius while it boils on a stove?: All the incoming energy goes into separating molecules from the liquid rather than making them move faster, so the temperature holds steady until the liquid is gone. A hotter burner only makes it boil away sooner, provided the pressure stays at one atmosphere. Chapter 09 · Temperature, Calorimetry and Heat Transfer
Why does gauge pressure give wrong answers in the gas law?: A tyre gauge reads the excess above the surrounding atmosphere, so a reading of 220 kPa corresponds to roughly 321 kPa absolute. The gas law relates the total force per area the molecules exert, which includes the atmospheric share. Add 1.013 × 10⁵ Pa to any gauge reading before substituting. Chapter 10 · Kinetic Theory and the Ideal Gas Law
Is heat the same thing as internal energy?: No. A system stores internal energy; heat is energy in transit across a boundary because of a temperature difference. A gas can gain internal energy with no heat at all, as in a rapid compression, and it can absorb heat with no internal energy change, as in a slow isothermal expansion. Chapter 11 · The First Law and Thermodynamic Processes
Does a larger amplitude make a spring oscillator take longer?: No. The period depends only on mass and spring constant, so pulling the block further simply means it covers more ground at higher speeds in the same time. The independence holds only while the spring obeys Hooke's law; overstretch it past its elastic limit and the result fails. Chapter 12 · Simple Harmonic Motion and Pendulums
Is the speed of a string element the same as the speed of the wave?: No. The wave speed depends only on tension and linear density, while each element moves up and down with a speed that changes through its cycle and peaks at omega times A. A high-frequency, large-amplitude wave can have elements moving faster than the wave itself, and a gentle wave can have them moving far slower. Chapter 13 · Travelling Waves, Superposition and Standing Waves
Why is the decibel scale logarithmic instead of linear?: Hearing responds roughly to ratios of intensity, and the range from a faint whisper to a painful noise covers a factor of about a trillion. A logarithm squeezes that span into roughly 0 to 120, and every tenfold rise adds the same 10 dB. Chapter 14 · Sound Waves, the Doppler Effect and Beats
Should I use the standard deviation or half the range for my trials?: For a small set, roughly fewer than ten trials, half the range works better, because a standard deviation from three or four values is itself unreliable. With a larger set the standard deviation is the better estimate. Either way, state which method you used so a demonstrator can follow the reasoning on the page. Chapter 15 · Measurement, Uncertainty and Straight-Line Graphs

Study strategy

How to study for the exam

Work the course as a problem-solving course, because both tests are almost entirely calculation. After each lecture, attempt that week's homework quiz until every question type has been answered correctly at least once, then repeat the quiz a few days later without notes.

Keep a running list of the formula-sheet lines you actually used and note the situations that call for each one; on test day the sheet is supplied, so the skill being tested is choosing the right line, not remembering it.

For every problem, draw the sketch or free body diagram first, write the principle in symbols, solve algebraically, and substitute numbers only at the end, which is the order the homework book itself recommends. Check units and the size of the answer before rounding to the shared number of significant figures.

Treat Tutorial Performance as non-negotiable: a sensible attempt in every tutorial from Week 2 earns the point, and the six automatic allowances are the only cushion. Prepare each lab with the pre-lab quiz and the dashed-box questions, and practise uncertainty propagation early, since it appears in every lab.

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