2.1.1
Motion in a Straight Line
Test your knowledge with free interactive questions on Seneca — used by over 10 million students.
Key Concepts of Motion
Displacement, speed, velocity and acceleration are fundamental concepts when describing motion in a straight line. You need to know how they link together.

Displacement
- The displacement of an object, s, is the distance and direction from an object's starting position to its final position.

Velocity and speed
- The velocity of an object, v, is the speed and direction an object is travelling.
- It is the rate of change of displacement:
- Speed is the magnitude of the velocity.
- Instantaneous speed/velocity is the speed/velocity of an object at a given instant in time.
- Average speed/velocity is the total distance/displacement divided by the total time taken.

Acceleration
- The acceleration of an object, a, is the rate (and direction) at which its velocity changes:

Delta symbol
- Delta, Δ, is the symbol meaning "change in".
- For example, Δs means change in displacement.
Uniform Acceleration Equations
These four equations describe motion along a straight line with uniform (constant) acceleration or deceleration.

Using the equations
- You will often be asked questions involving the 5 key concepts of motion in a straight line:
- s, displacement
- u, initial velocity
- v, final velocity
- a, acceleration
- t, time
- Usually you will be given three and asked to calculate a fourth using the 'suvat' equations, which are as follows...
1Physical Quantities & Units
1.1Physical Quantities & Units
2Kinematics
3Dynamics
3.1Momentum & Newton's Laws of Motion
3.2Non-Uniform Motion
3.3Linear Momentum & Conservation
4Force, Density & Pressure
4.1Force, Density & Pressure
4.1.1Fields4.1.2Force in Uniform Fields4.1.3Friction4.1.4Buoyancy4.1.5Terminal Speed4.1.6End of Topic Test - Acceleration Due to Gravity4.1.7Centre of Mass4.1.8Forces & Equilibrium4.1.9End of Topic Test - Scalars & Vectors4.1.10Moments4.1.11End of Topic Test - Moments & Centre of Mass4.1.12Density4.1.13Pressure
5Work, Energy & Power
6Deformation of Solids
7Waves
7.1Simple Harmonic Motion
7.2Waves
7.2.1Progressive Waves7.2.2Intensity of Waves7.2.3Wave Speed & Phase Difference7.2.4Longitudinal & Transverse Waves7.2.5End of Topic Test - Progressive Waves7.2.6Electromagnetic Waves7.2.7Doppler Effect7.2.8Sound Waves7.2.9Measuring Sound Waves7.2.10End of Topic Test - Waves7.2.11Ultrasound Imaging7.2.12Ultrasound Imaging 2
8Superposition
9Thermal Physics
9.1Circular Motion
9.2Thermal Physics
9.2.1Temperature9.2.2Measuring Temperature9.2.3Ideal Gas Law9.2.4Ideal Gases9.2.5Boyle's Law & Charles' Law9.2.6Molecular Kinetic Theory Model9.2.7Molecular Kinetic Theory Model 29.2.8Thermal Energy Transfer9.2.9Thermal Energy Transfer Experiments9.2.10End of Topic Test - Thermal Energy & Ideal Gases9.2.11First Law of Thermodynamics
10Communication
10.1Communication Channels
10.2Digital Communication
11Electric Fields
11.1Electric Fields
12Current Electricity
12.1Current Electricity
12.1.1Basics of Electricity12.1.2Mean Drift Velocity12.1.3Current-Voltage Characteristics12.1.4End of Topic Test - Basics of Electricity12.1.5Resistivity12.1.6End of Topic Test - Resistivity & Superconductors12.1.7Power and Conservation12.1.8Microphones12.1.9Components12.1.10Relays12.1.11Strain Gauges
13Magnetic Fields
13.1Magnetic Fields
14Modern Physics
14.1Quantum Physics
14.1.1The Photoelectric Effect14.1.2The Photoelectric Effect Explanation14.1.3End of Topic Test - The Photoelectric Effect14.1.4Collisions of Electrons with Atoms14.1.5Energy Levels & Photon Emission14.1.6Wave-Particle Duality14.1.7End of Topic Test - Absorption & Emission14.1.8Band Theory14.1.9Diagnostic X-Rays14.1.10X-Ray Image Processing14.1.11Absorption of X-Rays14.1.12CT Scanners
14.2Nuclear Physics
14.2.1Rutherford Scattering14.2.2Atomic Model14.2.3Isotopes14.2.4Stable & Unstable Nuclei14.2.5A-A* (AO3/4) - Stable & Unstable Nuclei14.2.6Alpha & Beta Radiation14.2.7Gamma Radiation14.2.8Particles, Antiparticles & Photons14.2.9Quarks & Antiquarks14.2.10Particle Interactions14.2.11Radioactive Decay14.2.12Half Life14.2.13End of Topic Test - Radioactivity14.2.14Nuclear Instability14.2.15Mass & Energy14.2.16Binding Energy14.2.17A-A* (AO3/4) - Nuclear Fusion
Jump to other topics
1Physical Quantities & Units
1.1Physical Quantities & Units
2Kinematics
3Dynamics
3.1Momentum & Newton's Laws of Motion
3.2Non-Uniform Motion
3.3Linear Momentum & Conservation
4Force, Density & Pressure
4.1Force, Density & Pressure
4.1.1Fields4.1.2Force in Uniform Fields4.1.3Friction4.1.4Buoyancy4.1.5Terminal Speed4.1.6End of Topic Test - Acceleration Due to Gravity4.1.7Centre of Mass4.1.8Forces & Equilibrium4.1.9End of Topic Test - Scalars & Vectors4.1.10Moments4.1.11End of Topic Test - Moments & Centre of Mass4.1.12Density4.1.13Pressure
5Work, Energy & Power
6Deformation of Solids
7Waves
7.1Simple Harmonic Motion
7.2Waves
7.2.1Progressive Waves7.2.2Intensity of Waves7.2.3Wave Speed & Phase Difference7.2.4Longitudinal & Transverse Waves7.2.5End of Topic Test - Progressive Waves7.2.6Electromagnetic Waves7.2.7Doppler Effect7.2.8Sound Waves7.2.9Measuring Sound Waves7.2.10End of Topic Test - Waves7.2.11Ultrasound Imaging7.2.12Ultrasound Imaging 2
8Superposition
9Thermal Physics
9.1Circular Motion
9.2Thermal Physics
9.2.1Temperature9.2.2Measuring Temperature9.2.3Ideal Gas Law9.2.4Ideal Gases9.2.5Boyle's Law & Charles' Law9.2.6Molecular Kinetic Theory Model9.2.7Molecular Kinetic Theory Model 29.2.8Thermal Energy Transfer9.2.9Thermal Energy Transfer Experiments9.2.10End of Topic Test - Thermal Energy & Ideal Gases9.2.11First Law of Thermodynamics
10Communication
10.1Communication Channels
10.2Digital Communication
11Electric Fields
11.1Electric Fields
12Current Electricity
12.1Current Electricity
12.1.1Basics of Electricity12.1.2Mean Drift Velocity12.1.3Current-Voltage Characteristics12.1.4End of Topic Test - Basics of Electricity12.1.5Resistivity12.1.6End of Topic Test - Resistivity & Superconductors12.1.7Power and Conservation12.1.8Microphones12.1.9Components12.1.10Relays12.1.11Strain Gauges
13Magnetic Fields
13.1Magnetic Fields
14Modern Physics
14.1Quantum Physics
14.1.1The Photoelectric Effect14.1.2The Photoelectric Effect Explanation14.1.3End of Topic Test - The Photoelectric Effect14.1.4Collisions of Electrons with Atoms14.1.5Energy Levels & Photon Emission14.1.6Wave-Particle Duality14.1.7End of Topic Test - Absorption & Emission14.1.8Band Theory14.1.9Diagnostic X-Rays14.1.10X-Ray Image Processing14.1.11Absorption of X-Rays14.1.12CT Scanners
14.2Nuclear Physics
14.2.1Rutherford Scattering14.2.2Atomic Model14.2.3Isotopes14.2.4Stable & Unstable Nuclei14.2.5A-A* (AO3/4) - Stable & Unstable Nuclei14.2.6Alpha & Beta Radiation14.2.7Gamma Radiation14.2.8Particles, Antiparticles & Photons14.2.9Quarks & Antiquarks14.2.10Particle Interactions14.2.11Radioactive Decay14.2.12Half Life14.2.13End of Topic Test - Radioactivity14.2.14Nuclear Instability14.2.15Mass & Energy14.2.16Binding Energy14.2.17A-A* (AO3/4) - Nuclear Fusion
Practice questions on Motion in a Straight Line
Can you answer these? Test yourself with free interactive practice on Seneca — used by over 10 million students.
- 1What does s represent?Multiple choice
- 2What is the correct formula for acceleration?Multiple choice
- 3Which equation for uniform acceleration is correct?Multiple choice
- 4Which suvat equation does NOT contain displacement?Multiple choice
Unlock your full potential with Seneca Premium
Unlimited access to 10,000+ open-ended exam questions
Mini-mock exams based on your study history
Unlock 800+ premium courses & e-books
