Karteikarten
OCR Gateway P3f
Karten in diesem Stapel (8)
- 1P3f - Crumple Zones.
- 2MomentumA moving object has momentum. This is the tendency of the object to keep moving in the same direction. It is difficult to change the direction of movement of an object with a lot of momentum.
- 3Calculating momentumMomentum = mass × velocity
Momentum is measured in kilograms metres per second, kg m/s
Mass is measured in kilograms, kg
Velocity is measured in metres per second, m/s - 4To reduce injuries in a collision, forces should be as small as possible.Force = Change in Momentum ÷ Time
Force is measured in newtons, N
Change in momentum is measured in kilograms metres per second, kg m/s
Time is measured in seconds, s - 5Spreading the momentum change over a longer time reduces the force. To minimise injury, forces acting on the people in the car during an accident must be minimised.Force = mass x acceleration
- 6Car Safety FeaturesModern cars have features that absorb energy when a vehicle stops suddenly. These are:
-Brakes that get hot
-Crumple Zones that change shape
-Seat belts that stretch a little
-Air bags that inflate and squash - 7Continue...On impact:
- Crumple zones at the front/rear of the car absorb some of its energy by changing shape or 'crumbling'
- Seat belts stretch a little so that some of the person's kinetic energy is converted to elastic energy.
- Air bags absorb some of the person's kinetic energy by squashing up around them. Air bags increase the time taken for the head's momentum to reach zero, so reduce the forces on it. - 8Preventing AccidentsOther safety features of cars are designed to reduce the chance of an accident happening. They include:
- Anti-lock braking system (ABS) – prevents skidding allowing the driver to remain in control. The vehicle stops more quickly as there's more friction between the road and tyres.
-Traction control - prevents skidding while accelerating so the car can quickly escape a dangerous situation.
- Safety cage – strengthens the cabin section to protect people in a roll-over accident.
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- Beschreibung
- Karteikarten am OCR Gateway P3f, erstellt von Zaaaara am 28/05/2014.
- Erstellt von
- Zaaaara
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- 47
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