P3c-forces And Motion Flashcards
What is gravity and weight?
Force always acting straight downwards
What is a reaction force from a surface?
Force acting straight upwards
What is thrust, push or pull due to an engine or rocket?
Force speeding something up
What is drag, air resistance or friction?
Force slowing the thing down
What is lift?
Force due to an aeroplane wing
What is tension?
Force in a rope or cable
What is thinking distance?
-distance travelled between the need for braking occurring and the brakes starting to act
What is braking distance?
The distance taken to stop once the brakes have been applied
What is stopping distance?
Thinking distance + braking distance
What factors increase thinking distance?
Driver tiredness
Influence of alcohol/drugs
Greater speed
Distractions/lack of concentration
What is aquaplaning?
When a tyre without tread rides on a layer of water and skids easily
What factors increase braking distance?
Road condition-wet icy roads slippery
Car conditions-heavier longer to stop
Greater speed- further it takes to stop
Why do cars need to leave enough space between them and the car in front?
- if they stop suddenly they have time to do so safely
- enough space is the stopping distance for the speed their going at
Why are speed limits important?
Speed affects the stopping distance
-faster = longer to stop
How does increased speed affect thinking distance?
Increases linearly
How does increased speed affect the braking distance?
Increases as a squared
What happens to braking distance if speed doubles?
Increases by a factor of four
What happens to braking distance if speed trebles?
Increases by a factor of nine
What is a force?
A push or pull
