Momentum Flashcards

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1
Q

What is the thinking distance?

A

The thinking distance is the distance travelled by the car as the driver reacts to apply the breaks.

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2
Q

What is the equation to work out thinking distance?

A

thinking distance (m) = speed of car (m/s) x reaction time (s)

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3
Q

What is braking distance?

A

Braking distance is the distance travelled by the car while the brakes are applied before the car comes to a stop.

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4
Q

What is the equation to work out braking distance?

A

stopping distance = thinking distance + braking distance

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5
Q

What 2 factors make the thinking distance increase?

A
  • when the speed of the car increases

- when the driver’s reaction time increases

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6
Q

What 3 things can cause the driver’s reaction time to increase?

A
  • tiredness
  • distraction
  • under the influence of drugs or alcohol
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7
Q

What 2 factors make the braking distance increase?

A
  • when the mass of the car increases

- when the speed of the car increases

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8
Q

How is friction created?

A

When 2 surfaces slide past each other, the interaction between them produces a force of friction.

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9
Q

What does a moving object have?

A

A moving object always has a momentum.

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10
Q

Why is momentum a vector quantity?

A

Momentum is a vector quantity as it has both a force and a direction.

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11
Q

What is the equation to work out momentum?

A

momentum (kg m/s) = mass (kg) x velocity (m/s)

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12
Q

What 2 things has momentum got?

A
  • magnitude

- direction

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13
Q

What is magnitude?

A

Magnitude is the amount of the object’s mass.

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14
Q

What does direction depend on?

A

Direction depends on the velocity of the object.

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15
Q

What is conserve momentum?

A

Where momentum stays the same in explosions and collisions.

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16
Q

What are seat belts and crumple zones designed to do?

A

Seat belts and crumple zones are designed to reduce the forces on the body if there is a collision.

17
Q

What do seat belts do?

A

Seat belts stop you moving around inside the car if there is a collision. However, they are designed to stretch slightly in a collision. This increases the time taken for the body’s momentum to reach zero, so reduces the forces on it.

18
Q

What do airbags do?

A

Air bags increase the time taken for the head’s momentum to reach zero, so reduce the forces on it. They also act a soft cushion and prevent cuts.

19
Q

What is the equation for force involved in changing the momentum of an object?

A

force (n) = change in momentum (kg m/s) divided by time (s)