What is meant by the stopping distance of a vehicle?

It is the total distance travelled from the driver seeing a hazard to the vehicle coming to rest.

What is meant by the thinking distance of a vehicle?

It is the distance travelled during the driver's reaction time, before the brakes are applied.

What is meant by the braking distance of a vehicle?

It is the distance the vehicle travels while the braking force is acting on it.

A car needs about 23 m to stop from 13 m/s. Explain why stopping from 27 m/s takes far more than twice this distance.

The thinking distance doubles with speed, but the braking distance grows much faster than that, so the total is more than doubled.

Which part of the stopping distance is directly proportional to the vehicle's speed?

The thinking distance, because the reaction time stays the same while the vehicle travels further in it.

AQA GCSE Combined Science Physics 8464

Atomic Structure

Topic overview The structure of an atom Mass number, atomic number and isotopes From the plum pudding model to the nuclear model Chadwick, the neutron, and comparing the models Radioactive decay and nuclear radiation Nuclear equations Half-lives and the random nature of radioactive decay Radioactive contamination

Electricity

Topic overview Circuit symbols, electrical charge and current Current, resistance and potential difference Ohmic conductors, filament lamps, diodes and thermistors Light-dependent resistors, and investigating resistance Current and potential difference in series and parallel Constructing circuits, and calculating in series circuits Direct and alternating potential difference, and mains electricity Power and efficiency Appliances, and the energy transferred by electrical work Power, and the power ratings of domestic appliances The National Grid

Energy

Topic overview Energy stores and systems Kinetic energy Elastic and gravitational potential energy Energy changes in systems Power Energy transfers in a system The main energy resources, renewable and non-renewable Environmental impact and trends in energy use

Forces

Topic overview Scalars, vectors, forces and the resultant force Gravity Work done and energy transfer Stretching, compressing, and the spring constant Linear and non-linear extension, and work done on a spring Distance, displacement and speed The speed of sound, and the distance-speed-time equation Velocity and the distance-time relationship Acceleration, deceleration and velocity-time graphs Area under a velocity-time graph, and the uniform acceleration equation Newton's First Law Newton's Second and Third Laws Stopping distance and reaction time Factors affecting braking distance Braking force, deceleration and the dangers of stopping quickly

Magnetism and Electromagnetism

Topic overview Poles of a magnet Magnetic fields around a magnet The compass, and plotting a magnetic field Electromagnetism

Particle Model of Matter

Topic overview Density of materials Changes of state and internal energy Temperature changes in a system and specific heat capacity Changes of state and specific latent heat Particle motion in gases

Waves

Topic overview Transverse and longitudinal waves, and the wave equation Wave properties, and refraction at a boundary Types and uses of electromagnetic waves Radio waves, and the hazards of ultraviolet, X-rays and gamma rays

Forces

Stopping distance and reaction time

3 things to know
Physics Paper 2

Overview

Stopping, thinking and braking distance, how an increase in speed affects stopping distance, how reaction times vary and the things that lengthen them, measuring reaction time with a ruler-drop test and repeating it, and why a tired driver has a longer thinking distance.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

For a given braking force, how does an increase in speed affect the stopping distance?

Key term

State the range of typical values for human reaction time.

Key term

Name three things that can lengthen a driver's reaction time.

Questions from this subtopic

Each one with the model answer underneath.

1
What is meant by the stopping distance of a vehicle?
Model answer
It is the total distance travelled from the driver seeing a hazard to the vehicle coming to rest.
2
What is meant by the thinking distance of a vehicle?
Model answer
It is the distance travelled during the driver's reaction time, before the brakes are applied.
3
What is meant by the braking distance of a vehicle?
Model answer
It is the distance the vehicle travels while the braking force is acting on it.
4
For a given braking force, how does an increase in speed affect the stopping distance?
Model answer
The greater the speed, the greater the stopping distance.
5
A car needs about 23 m to stop from 13 m/s. Explain why stopping from 27 m/s takes far more than twice this distance.
Model answer
The thinking distance doubles with speed, but the braking distance grows much faster than that, so the total is more than doubled.
6
Which part of the stopping distance is directly proportional to the vehicle's speed?
Model answer
The thinking distance, because the reaction time stays the same while the vehicle travels further in it.

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