Linear Motion and Dynamics

What Linear Motion and Dynamics covers

Linear Motion and Dynamics is examined in Unit AS 1, Forces, Energy and Electricity, and drawn on again in Unit AS 3, Practical Techniques and Data Analysis. It covers displacement, velocity and acceleration, the equations of motion for uniform acceleration, measuring the acceleration of free fall with light gates, displacement–time and velocity–time graphs, projectile motion and projectile calculations.

The 6 subtopics

Each one has its own page. CCEA AS Physics students sit this topic in the first year.

• Displacement, velocity and accelerationVelocity and state its SI unit, average velocity and acceleration and state its SI unit.Open →
• The equations of motion for uniform accelerationRecall questions on the four suvat equations and when they may be used, choosing the right one when time or final velocity is unknown, the sign convention for vertical motion, worked problems on a car accelerating and braking and a stone dropped or thrown upwards, and why a journey in stages cannot be done in one step.Open →
• Measuring the acceleration of free fall with light gatesRecall questions on the apparatus and procedure for the two-light-gate method, how the software gets the velocity at each gate, the two equations for g from the velocities, why the interrupt card must pass squarely through the beam, the trade-off in card length, and the main sources of uncertainty.Open →
• Displacement–time and velocity–time graphsRecall questions on what the gradient of each graph represents and what the area under a velocity–time graph gives, the shapes for constant velocity and for uniform acceleration, negative gradients and areas below the axis, finding an instantaneous acceleration from a curve, and worked problems on a vehicle and a train.Open →
• Projectile motionProjectile motion as the combination of two separate motions, why the horizontal velocity of a projectile stays constant and acceleration of a projectile at every point of its flight.Open →
• Projectile calculationsRecall questions treating the horizontal and vertical motions separately: time of flight and range for a ball leaving a bench, the components of a launch velocity at an angle, maximum height, total flight time and range over level ground, and why the horizontal component never changes.Open →

What you need to know

Answer each one before you reveal it.

Take Linear Motion and Dynamics further

The same content, four other ways.

Commonly confused

Pairs that lose marks when they are blurred together.

• Uniform acceleration vs Uniform velocity

  Uniform acceleration: the rate of change of motion is steady, so the speed keeps altering. Uniform velocity: nothing is changing at all, so the body travels in a straight line at a fixed rate.

• A deceleration always vs A negative acceleration always

  A deceleration always: the object is slowing down. A negative acceleration always: it only means the change is directed along the axis chosen as the minus direction, which speeds the object up if it is already travelling that way.

Questions from this topic

Each one with the model answer underneath.

1. 1

   Define displacement.

   Model answer

   Displacement is the straight-line distance of an object from a stated starting point, measured in a stated direction, and it is a vector quantity measured in metres.

2. 2

   Define velocity and state its SI unit.

   Model answer

   Velocity is the rate of change of displacement, a vector quantity measured in metres per second (m s⁻¹).

3. 3

   Define average velocity.

   Model answer

   Average velocity is the total displacement divided by the total time taken for that displacement, and it is quoted with a direction.

4. 4

   Define acceleration and state its SI unit.

   Model answer

   Acceleration is the rate of change of velocity, a vector quantity measured in metres per second squared (m s⁻²).

5. 5

   State the equation for average velocity, defining each symbol and its unit.

   Model answer

   Average velocity is v̄ = Δs/Δt, where v̄ is in m s⁻¹, Δs is the total displacement in metres and Δt is the total time taken in seconds.

6. 6

   State the equation for uniform acceleration in terms of initial and final velocity, defining each symbol and its unit.

   Model answer

   Acceleration is a = (v − u)/t, where a is in m s⁻², u is the initial velocity in m s⁻¹, v the final velocity in m s⁻¹ and t the time taken in seconds.

What is inside Levo

Six ways to work the same material.

Linear Motion and Dynamics revision questions

Is Linear Motion and Dynamics examined at AS in CCEA Physics?

Yes. It sits in Unit AS 1, which you take in the first year, so it is on the AS paper as well as counting towards the full A level.

What does Linear Motion and Dynamics cover in CCEA AS-Level Physics?

6 subtopics: displacement, velocity and acceleration, the equations of motion for uniform acceleration, measuring the acceleration of free fall with light gates, displacement–time and velocity–time graphs, projectile motion and projectile calculations. Each one has its own page with questions and model answers.

How is Linear Motion and Dynamics organised?

By the CCEA 1210 specification, subtopic by subtopic, so it matches the order you are taught it in.