Difference between revisions of "Braking Distance"
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Where: | Where: | ||
− | s is the [[ | + | s is the [[Braking Distance|braking distance]] |
𝑣 is the initial [[velocity]] of the [[object]] | 𝑣 is the initial [[velocity]] of the [[object]] | ||
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a is the [[acceleration]] of the [[object]] (in this case it is referred to as deceleration and if the velocity is chosen to be in a positive direction, the acceleration must be given a negative value). | a is the [[acceleration]] of the [[object]] (in this case it is referred to as deceleration and if the velocity is chosen to be in a positive direction, the acceleration must be given a negative value). | ||
+ | |||
When considering the [[friction]]al [[force]]s involved between surfaces such as the tyre and the road surface for a car then then [[Braking Distance|Braking distance]] can be given by the formula: | When considering the [[friction]]al [[force]]s involved between surfaces such as the tyre and the road surface for a car then then [[Braking Distance|Braking distance]] can be given by the formula: | ||
− | <math>s=𝑣^2 | + | <math>s=\frac{𝑣^2}{2𝜇𝑔}</math> |
Where: | Where: | ||
− | s is the [[ | + | s is the [[Braking Distance|braking distance]] |
𝑣 is the initial [[velocity]] of the car | 𝑣 is the initial [[velocity]] of the car |
Latest revision as of 13:53, 22 May 2024
Contents
Key Stage 4
Meaning
Braking distance is the distance a vehicle travels from the moment the brakes are applied to the moment the vehicle stops.
About Braking Distance
Braking distance makes up one of two parts of the stopping distance of a vehicle.
Braking distance depends on:
- The speed of the vehicle - The greater the speed the larger the braking distance.
- The conditions of the road and tyres - The less friction between the road and tyres the longer the braking distance. Water, oil or ice on the road all reduce the friction between the tyres and the road, causing the braking distance to be greater than for a dry road. Different road surfaces have different amounts of friction. The painted lines on the road and the metal of a manhole cover are both low friction surfaces which are especially dangerous for motorcycles which only have two wheels (at least with 4 wheels a car will have 3 of them on the normal road with 1 on the slippery surface of a line or manhole cover).
- The condition of the brakes, if they are in poor condition there will not be enough friction.
- The mass of the car. The more mass a car has the more force is required to slow it down so brakes providing a constant force won't be as effective. Higher: See Inertial Mass.
- Weather conditions - Ice reduces friction with the road making braking distance longer.
References
AQA
- Braking distance, page 166, GCSE Physics; Student Book, Collins, AQA
- Braking distance, pages 148-149, 157, GCSE Physics; Third Edition, Oxford University Press, AQA
- Braking distance, pages 67, 69, GCSE Physics; The Revision Guide, CGP, AQA
- Braking distances, pages 10, 163-4, GCSE Physics, Hodder, AQA
- Braking distances, pages 10, 163-4, GCSE Physics, Hodder, AQA
- Braking distances, pages 176-178, GCSE Combined Science Trilogy; Physics, CGP, AQA
- Braking distances, pages 208-210, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA
- Braking distances, pages 215, 216, GCSE Combined Science; The Revision Guide, CGP, AQA
- Braking distances; influencing factors, page 165, GCSE Physics, Hodder, AQA
Edexcel
- Braking distance, pages 26, 28-29, GCSE Physics, Pearson Edexcel
- Braking distance, pages 310, 311, GCSE Combined Science, Pearson Edexcel
- Braking distances, page 155, GCSE Combined Science; The Revision Guide, CGP, Edexcel
- Braking distances, pages 22, 23, GCSE Physics; The Revision Guide, CGP, Edexcel
- Braking distances, pages 49-52, GCSE Physics, CGP, Edexcel
- Braking distances; work done in braking, page 52, GCSE Physics, CGP, Edexcel
OCR
- Braking distance, pages 220-221, Gateway GCSE Physics, Oxford, OCR
- Braking distances, page 210, Gateway GCSE Combined Science; The Revision Guide, CGP, OCR
Key Stage 5
Meaning
Braking distance is the distance traveled by a vehicle in the time taken to stop it.
About Braking Distance
- Braking distance depends on the vehicle's speed, mass, and the condition of the brakes.
- The braking distance of a vehicle on the road is affected by road conditions, tire quality and the conditions of the brakes.
- Braking distance is part of the total stopping distance, which also includes thinking distance with depends upon reaction time.
Formula
Braking distance can be given by the formula\[s=\frac{𝑣^2}{2a}\]
Where:
s is the braking distance
𝑣 is the initial velocity of the object
and
a is the acceleration of the object (in this case it is referred to as deceleration and if the velocity is chosen to be in a positive direction, the acceleration must be given a negative value).
When considering the frictional forces involved between surfaces such as the tyre and the road surface for a car then then Braking distance can be given by the formula\[s=\frac{𝑣^2}{2𝜇𝑔}\]
Where:
s is the braking distance
𝑣 is the initial velocity of the car
μ is the coefficient of friction
and
g is the acceleration due to gravity or Gravitational Field Strength.
Examples
- At higher speeds, the braking distance increases significantly.
- Wet or icy roads increase the braking distance due to reduced friction.