# Physics: P2.2 The kinetic energy of objects speeding up or slowing down

• Created by: shcoool
• Created on: 26-05-15 16:29
What is meant when 'work is done'
a force causes an object to move through a distance
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How do you work out the work done?
W = F * d
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What happens when work is done?
energy is transferred
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What is power and how do you work it out?
power is work done or energy transferred in a given time P = E/t
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What is gravitational potential energy and how do you work it out?
The energy that an object has by virtue of its position in a gravitational field E = m*g*h
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What does kinetic energy depend on?
It depends on its mass and its speed - E = 0.5 * m * v(SQUARED)
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What is momentum?
It is a property of moving objects - p = m * v
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What is the conservation of momentum?
In a closed system the total momentum before an event is equal to the total momentum after the event
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How do seat belts, crumple zones and air bags reduce the impact of a crash on humans?
seat belts - increase time taken for momentum to get to zero of a human, air bags - increase time taken for head's momentum to get to zero, crumple zones - increase time of impact so less energy is transferred.
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## Other cards in this set

### Card 2

#### Front

How do you work out the work done?

W = F * d

### Card 3

#### Front

What happens when work is done?

### Card 4

#### Front

What is power and how do you work it out?

### Card 5

#### Front

What is gravitational potential energy and how do you work it out?