# Turning forces and Centre of Mass

AQA Physics P3 (i)

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## Moment

Turning effect of a force

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## Equation for Moments (Nm)

FORCE (N) * perpandicular DISTANCE (M) between line of action and pivot

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## Examples.

Larger force = larger moments. For example. the force on a spanner causes a turning effect or moment on the nut. If the force was 10N and the distance was 10cm the equation would be 10*0.1=1Nm

A spannner 20 cm in length would have this equation: 10*0.2= 2Nm

To get the maximum moment, push at right angles to the spanner.

Any other angles mean a smaller moment because perp. distance of line of action and pivot is smaller.

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## Centre of mass is the point all of the mass is con

The centre of mass hangs directly below the point of suspension.

An object will swing until its CoM is vertically below the point of suspension.

You can find centre of mass of a simple shape, but drawing on lines of symmetry. Where the lines meet is the centre of mass.

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