Momentum and Car Safety Flashcards
What is momentum?
A property of moving objects.
What is the momentum formula?
Momentum = Mass x Velocity kgm/s = kg x m/s
What is the Conservation of Momentum?
Momentum before = momentum after
When does the Conservation of Momentum apply?
In a closed system.
What causes a change in momentum?
Forces.
Why are car crashes dangerous?
A big change in momentum over a short time means the passengers experience huge forces.
What are four examples of car safety features?
- Crumple zones
- Seat belts
- Side impact bars
- Air bags
How do crumple zones help?
- Convert kinetic energy as they change shape
2. Increase impact time
How do seat belts help?
- Increase time taken to stop
- Reduces forces in chest
- Some kinetic energy absorbed by stretching
How do side impact bars help?
Direct energy away from passengers to other areas e.g crumple zones
How do air bags help?
- Slows passengers down slowly
2. Prevents hitting hard surfaces
What happens when you apply the brakes?
Work is done.
How do brakes work?
They convert kinetic energy of the car into heat and sound energy.
How do regenerative braking systems work?
- Brakes put motor into reverse, slowing wheels
- Motor acts as electrical generator
- Kinetic energy turns into electrical energy
- Electrical energy is stored as chemical energy in battery
What is the advantage of regenerative braking systems?
They store the energy of braking rather than wasting it.
