P3 Forces For Transport Flashcards
When 2 cars move past each other what is their relative velocity
The sum of their individual velocities if they are going in opposite directions, the difference of their individual velocities if they are going in the same directions
Why is a car accelerating if it is going at a constant speed if it is going in a circular motion
Because the driver needs to apply a force towards the centre of the roundabout to change direction, this gives the vehicle an acceleration directed towards the centre of the roundabout
What affects reaction time
Tiredness, under the influence of alcohol or drugs, travelling faster, distracted
What affects braking distance
The road conditions, how well the car is maintained, like brakes, the speed of the car and the weight of the car
What is work done
When a force moves an object in the direction in which the force acts
What is weight
A measure of the gravitational attraction on a body aching towards the centre of the earth
What is power
The rate at which work is done
What are the factors which affect fuel consumption of a car
The amount of energy required to increase its kinetic energy, the amount of energy required for it to do work against friction, it’s speed, how it’s driven such as constant braking and speed changes, road conditions
What are the negatives of electric powered cars
Battery takes up a lot of room, limited range before recharging, expensive to buy, when it is filled up, it requires electricity which comes from power stations which use fossil fuels anyway
What are some alternatives to electric and petrol powered cars
Biofuels dans solar-powered cars
Name some safety features in cars
Brakes that get hot, crumple zone new, seat belts, air bags
What do all safety features in cars do
Absorb energy, change shape, reduce injuries, reduce momentum to zero slowly, therefore reducing the force on the occupants
Why might some people not want to wear seat belts
Risk of chest injury, could be trapped in a fire, drivers may be encouraged to drive less carefully when they wear a seatbelt as they naturally feel safer
What do ABS brakes do
They prevent wheels from locking up by sending information to a computer about the speed of the wheels
What happens at terminal velocity and why
You remain at a certain speed because the air resistance and weight of the object are equal
