Centre of Mass

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• Created by: Heather
• Created on: 17-05-14 18:58
What is the definition of centre of pass?
The point of an object at which the mass may be thought to be concentrated,
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When does a suspended object reach equilibrium?
When the weight of the object doesnt exert a turning effect on the object as its centre of mass is directly below the point of suspension,
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How do you find the centre of mass from a symettrical object?
It is the point where all the lines of symmetry meet up,
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How do you find the centre of mass from an irregular shape?
Suspend the shape by drilling a small hole into it in the edge and hang it up so it is suspended freely as well as a plumb line so both hang freely. Draw line where plump line is. Repeat at different point in shape. Where lines meet up=centre of mass
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What is the principle of moments?
The sum of all the clockwise moments about any point=the sum of all the anticlockwise moments about that point,
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What factors affect the stability of an object?
-The size of the base, -The height of the centre of mass,
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When will an object topple over?
When the line of action of its weight is outside its base,
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Why does it topple over if the line of action is outside its base?
As the resultant moment makes the object topple as the clockwise moment doesnt equal the antoclockwise moment so it topples,
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What is pressure defined as and the unit?
As force per unit of area in pascal, Pa
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The pressure in a liquid acts _ _ _ _ _ _ _ in _ _ _ directions,
The pressure in a liquid acts equally in all directions,
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What do mechanical diggers use/ are called?
Hydraulic pressure systems,
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Why is pressure in water transmitted in all directions?
As liquid is virtually incompressible so the volume doesnt change when under pressure,
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The force of a hydraulic system is much what then the force applied?
Greater
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What is the motion of a pendulum or a swing called and what does it mean?
An oscillating motion-the motion of an object that moves to and fro along the same line,
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What is the amplitude of an oscillating object?
The distance from the equilibrium position at the lowest point to the highest position on either side,
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What is the time period of a pendulum?
The time taken for one complete cycle of its motion,
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What is the number of complete cycles of oscillation per second called?
The frequency
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What is the equation to find out the time period of a pendulum?
Time period = 1 / frequency of oscillations
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What is the unit of the time period?
Seconds, S
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What is the unit of frequncy?
Hz, Hertz,
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What will stop a pendulum from swinging?
The friction at the top of the swing and air resistance,
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Other cards in this set

Card 2

Front

When does a suspended object reach equilibrium?

Back

When the weight of the object doesnt exert a turning effect on the object as its centre of mass is directly below the point of suspension,

Card 3

Front

How do you find the centre of mass from a symettrical object?

Card 4

Front

How do you find the centre of mass from an irregular shape?

Card 5

Front

What is the principle of moments?