# Unit 2 Physics Speed

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• Created by: Sunset
• Created on: 03-01-14 08:47
How is momentum calculated?
Mass x Velocity
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What is the total momentum before and after an explosion?
0 Kgms-1
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How is power calculated?
Work done (J) /Time taken (s)
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What is the only factor that affects thinking distance and braking distance (stopping distances)?
Speed
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How does speed affect braking distance?
If you double speed you quadruple braking distance
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What are the two ways of calculating acceleration?
V-U/T or F/M
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When using F=MA, what are the units of M?
Kg
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What does Newtons First Law state?
An objects velocity remains constant until a resultant force acts on it
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What is the resultant force: 17N to the left and 12N to the right?
5N left
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What does the gradient on a V-T graph denote?
Acceleration
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What does the gradient on a D-T graph denote?
Speed
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What are the units of velocity?
ms-1
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What are the units of acceleration
ms-2
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How does a seatbelt improve car safety?
It lengthens the time taken for the persons velocity to reach 0 and the force is applied over a large surface area
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If the spring constant is 2Nm-1 and a spring extends 6m, what force was applied?
12N
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What is the law of conservation of mass?
Momentum Before = Momentum After
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If a girl who weighs 15Kg runs 2m upstairs in 2s, what is her power?
150W (15 x 10 = 150N, 150 x 2 = 300J, 300/2 =150W)
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What is the kinetics energy of a ball that is moving at 6ms-1 with a mass of 1kg?
18J
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## Other cards in this set

### Card 2

#### Front

What is the total momentum before and after an explosion?

0 Kgms-1

### Card 3

#### Front

How is power calculated?

### Card 4

#### Front

What is the only factor that affects thinking distance and braking distance (stopping distances)?

### Card 5

#### Front

How does speed affect braking distance?