What does the Mechanics strand in OCR Maths A cover?

It covers quantities and units (SI units, scalars and vectors, and modelling assumptions), kinematics (displacement, velocity and acceleration, the suvat equations, motion under gravity, motion graphs and variable acceleration with calculus), forces and Newton's laws (resolving forces, equilibrium, friction, inclined planes and connected particles), projectiles (resolving the launch velocity and treating horizontal and vertical motion independently), and moments (the turning effect of forces and the equilibrium of rigid bodies). It is assessed in Paper 3 alongside Pure.

Which Mechanics topics carry the most marks in OCR Maths A?

Forces and Newton's laws and kinematics are the heaviest, because equations of motion, friction and connected particles appear as long structured questions, and the suvat equations underpin projectiles too. Projectiles and moments are reliable high-tariff questions. Fluency with resolving forces and selecting the right suvat equation is the single biggest mark-winner, since almost every mechanics question begins with one of those steps.

What techniques recur across the OCR Mechanics content?

Resolving a force into perpendicular components, choosing the suvat equation that omits the unwanted variable, applying Newton's second law along and perpendicular to motion, computing friction as the coefficient times the normal reaction, resolving the launch velocity of a projectile and using the independence of the two motions, and taking moments about a chosen point to eliminate an unknown reaction. These are automatic by exam day.

What is the most common Mechanics mistake in OCR Maths A?

Sign errors under gravity and applying g horizontally in projectile motion. Other frequent errors are swapping sine and cosine for slope components, forgetting that the normal reaction on a slope is mg cos theta not mg, assuming friction is always its maximum value, confusing distance with displacement when velocity changes sign, and placing a non-uniform rod's weight at the midpoint. Always fix a positive direction first and keep units consistent.

How should I revise the OCR Mechanics content?

Work topic by topic against the specification, drilling each technique until it is automatic, then practise mixed problems under timed conditions. Always draw a clear force diagram, fix a positive direction, and keep units in kilograms, metres and seconds. Keep a sheet of standard results: the suvat equations, the slope components mg sin theta and mg cos theta, the friction law, the projectile time of flight and range, and the principle of moments. Use g = 9.8 m per second squared throughout.

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OCR A-Level Maths A Mechanics: units, kinematics, forces, projectiles and moments

A deep-dive OCR A-Level Mathematics A guide to the Mechanics strand: quantities and units, kinematics and the suvat equations, forces and Newton's laws, projectiles, and moments, with the modelling assumptions and techniques OCR repeats in Paper 3.

Generated by Claude Opus 4.820 min readH240/3.01-3.04Updated 2026-06-02

Reviewed by: AI editorial process; not yet individually human-reviewed

Jump to a section

What the Mechanics strand demands
Quantities and kinematics
Forces and Newton's laws
Projectiles and moments
How the Mechanics content is examined
Check your knowledge

What the Mechanics strand demands

The Mechanics strand of OCR A-Level Mathematics A (H240) sits alongside Pure in Paper 3 (Pure Mathematics and Mechanics). It applies the pure techniques, especially trigonometry, vectors and calculus, to motion and forces. The examiners reward a clear model (a labelled force diagram and stated assumptions), consistent units, and fluent technique with the standard equations.

This guide walks through the four Mechanics topics in specification order, then sets out the exam patterns OCR repeats. Each topic has a matching dot-point page with worked exam questions; this overview ties them together.

Quantities and kinematics

Quantities and units in mechanics (3.01) covers the SI base and derived units, the distinction between scalar and vector quantities, and the modelling assumptions (particle, light, inextensible, smooth, rigid). Kinematics (3.02) covers displacement, velocity and acceleration, the suvat equations for constant acceleration, motion under gravity, displacement-time and velocity-time graphs, and the use of differentiation and integration when acceleration varies with time.

Forces and Newton's laws

Forces and Newton's laws (3.03) covers the three laws, weight $W = mg$ , resolving forces into perpendicular components, the equilibrium of a particle, friction with $F \le \mu R$ , motion on an inclined plane (with weight components $mg\sin\theta$ down the slope and $mg\cos\theta$ into it), and connected particles over a smooth pulley. Newton's second law, resultant force $= ma$ , is the master equation of the strand.

Projectiles and moments

Projectiles treats motion under gravity in two dimensions by resolving the launch velocity into $u\cos\theta$ and $u\sin\theta$ and using the independence of the horizontal motion (constant velocity) and the vertical motion (constant acceleration $g$ ), to find the time of flight, range and greatest height. Moments (3.04) covers the turning effect of a force, the principle of moments, and the equilibrium of rigid bodies such as uniform and non-uniform rods, including finding reactions and tilting conditions.

How the Mechanics content is examined

A typical OCR profile for the Mechanics strand:

Technique questions. Resolving a force, choosing a suvat equation, computing friction, or finding a moment.
Equation-of-motion problems. A block on a rough surface or slope, or connected particles over a pulley.
Projectile problems. Time of flight, range, height, or whether a projectile clears an obstacle.
Rigid-body problems. Reactions on a loaded beam, the centre of mass of a non-uniform rod, or a tilting condition.

Check your knowledge

A mix of recall and technique questions covering the Mechanics content. Attempt them under timed conditions, then check against the solutions.

State the suvat equation that does not involve time. (1 mark)
A $3$ kg mass has weight how many newtons? ( $g = 9.8$ ) (1 mark)
A force of $10$ N acts at $60^\circ$ to the horizontal. Find its horizontal component. (2 marks)
A projectile is launched at $20$ m s $^{-1}$ at $30^\circ$ . Find the horizontal component of velocity. (2 marks)
State the friction law for a body on the point of sliding. (1 mark)
A $40$ N force acts $0.5$ m from a pivot, perpendicular to the arm. Find the moment. (1 mark)

Solutions

Step 1: Recall the correct kinematic equation

The five SUVAT equations link displacement, velocity, acceleration, and time. When time is not given or required, use the equation that connects $v$ , $u$ , $a$ , and $s$ directly.

v^2 = u^2 + 2as

Step 2: Calculate the weight of the object

Weight is the gravitational force on an object, found by multiplying mass by the gravitational field strength $g = 9.8$ m s $^{-2}$ . This converts a mass in kg to a force in newtons.

W = mg = 3 \times 9.8 = 29.4 \text{ N}

Step 3: Resolve the force horizontally

To find the horizontal component of a force acting at an angle, multiply the magnitude by the cosine of the angle from the horizontal. Here $\cos 60^\circ = 0.5$ .

10\cos 60^\circ = 10 \times 0.5 = 5 \text{ N}

Step 4: Find the horizontal component of the launch velocity

The horizontal velocity component is unchanged throughout the flight (ignoring air resistance), and is found by resolving the initial speed along the horizontal direction using cosine.

u_x = 20\cos 30^\circ = 20 \times \tfrac{\sqrt{3}}{2} \approx 17.3 \text{ m s}^{-1}

Step 5: State the friction law at the point of sliding

Friction takes its maximum (limiting) value $F = \mu R$ exactly when the object is on the point of sliding. The coefficient $\mu$ depends on the surfaces in contact and $R$ is the normal reaction force.

F = \mu R

Step 6: Calculate the moment of the force

The moment of a force about a pivot equals the force multiplied by the perpendicular distance from the pivot. Since the force acts perpendicular to the arm, the full distance of $0.5$ m is used.

40 \times 0.5 = 20 \text{ N m}

Sources & how we know this

OCR A Level Mathematics A (H240) specification — OCR (2017)