Momentum Flashcards
What is momentum?
A property all moving objects have
Units of momentum?
Kg m/s
In a closed system, what does the total momentum before an event equal?
Total momentum after an event
What is the conservation of momentum?
Total momentum before = total momentum after
How do seat belts work?
Increase time taken for the wearer to stop, reducing acceleration and the forces acting on their chest
Some kinetic energy absorbed by the seat belt stretching
How do air bags work?
Slow you down more gradually, and prevent you from hitting hard surfaces
How do side impact bars work?
Direct kinetic energy away from passengers to other areas of the car like crumple zones, meaning less force exerted on you
How do crumple zones work?
Kinetic energy converted as other energy as the car body changes shape
Increase the amount of impact time, decreasing the force produced by the change in momentum
How do regenerative brakes work?
The brakes put the motor in reverse, slowing wheels down, at the same time, the motor converts kinetic energy into electrical energy that’s stored as chemical energy
What’s the benefit of regenerative braking?
They store energy instead of wasting it
