[6] Momentum Flashcards

1
Q

Equation for momentum

A

P = MV

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2
Q

Momentum = Mass x Velocity

If Acceleration = V - U / T then,

Newton’s 2nd Law F = MA means that …

A

F = M(V - U / T)

F = MV - MU / T

MV - MU is change of momentum

MV - MU / T is rate of change of momentum

FT is the impulse

Safety features such as airbags and seat belts increase the time at which the drivers, passengers and car experience a collision , which decreases the size of the force exerted.

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3
Q

What purpose do crumple zones which are implemented into car design serve in the event of a car crash?

A

Crumple zones at the front and rear which collapse in such a way that the energy is absorbed gradually.

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4
Q

What purpose do seat belts which are implemented into car design serve in the event of a car crash?

A

Seat belts exert a force backwards to stop the driver and passengers colliding with the windscreen or back of seat.

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5
Q

Recite the principle of conservation of momentum

A

The principle of conservation of momentum states that when two or more bodies act on one another, as in a collision, the total momentum of the bodies remains constant, provided no external forces act.

The simple form of this law is: ‘The total momentum of two bodies before a collision = The total momentum after a collision.’

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6
Q

What purpose do air bags which are implemented into car design serve in the event of a car crash?

A

Air bags in some cars inflate and protect the driver from injury by the steering wheel because the airbag changes shape as the person’s body strikes it causing the time over which the person comes to a halt to increase and so reduces the size exerted on them. The area of contact with the body is greatly increased compared to the area if the person’s chest struck the steering wheel.

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7
Q

What purpose do crash barriers which are implemented into public roadways serve in the event of a car crash?

A

Crash barriers in the central reservation of roads, at the surrounding fields and in front of the concrete supports for bridges are designed to deform when struck by a car and increase the time over which the speed of the car is reduced and also to keep the car on the correct side of the road.

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