Point where the entire weight of an object appears to act
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Describe an experiment to find the centre of gravity of an object
1. Hang object freely from a point // 2. Hang plumb line from the same point and draw vertical line from point of suspension // 3. repeat 2/3 times until lines cross // 4. centre of gravity is where lines cross
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What is a couple?
pair of forces that tends to produce rotation only
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What is a torque of a couple?
product of one of the forces and the perpendicular distance between them
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How do you calculate the torque of a couple?
one force x perpendicular distance between
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What is the moment of a force?
magnitude of a force multiplied by the perpendicular distance from the point to the line of action
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How do you calculate a moment of a force?
force x perpendicular distance from pivot / axis / point
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Describe a couple
pair of equal and opposite forces that tend to produce rotation only // lines of action do not intersect // cannot produce a resultant force
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What is equilibrium?
when an object is at rest or travelling with a constant velocity because net force and moment both = 0
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Describe a body in equilibrium
object does not change in it's motion // acceleration 0 // resultant net fore, linear acceleration, resultant net moment and anger acceleration is all 0
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What is the principle of moments?
the sum of the clockwise moment about a point is equal to the sum of the anti-clockwise moments about the same point
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What is density?
the mass per unit volume of a substance
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What does density depend on?
mass of each of its atoms // the way the atoms are packed together
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What is pressure?
'normal' force per unit area acting on a surface
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What is a pascal?
measure of pressure, newton per metre^2
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Other cards in this set
Card 2
Front
Describe an experiment to find the centre of gravity of an object
Back
1. Hang object freely from a point // 2. Hang plumb line from the same point and draw vertical line from point of suspension // 3. repeat 2/3 times until lines cross // 4. centre of gravity is where lines cross
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