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Moment of a force: It is the product of force and the perpendicular distance (between the line of action of the force and the pivot).
Moment of a force = F x d
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Moments can be clockwise or anticlockwise.
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The Principle of Moments: For a body in equilibrium, the sum of clockwise moments is equal to the sum of anticlockwise moments.
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Example:
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Centre of mass: It is the point through which the whole weight of an object seems to act for any orientation of the object.
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Centre of mass of an object (such as ring) can lie outside the object.
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Experiment to determine centre of mass of a plane lamina
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The marking points are:
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set metal swinging (to ensure minimal friction at pivot)
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allow to come to rest
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use of plumb line from hole
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mark line along plumb line (on metal)
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hang from another hole
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hang from 3 rd hole
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point of intersection of lines is centre of mass
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Stability: It is the ability of an object to regain its original position after it has been tilted slightly.
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Stability can be improved by
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lowering the centre of mass
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increasing the broadness of base
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