Prove that

Moment of couple = Force x Couple arm.

Describe a simple experiment to verify the principle of moments, if you are supplied with a metre rule, a fulcrum and two springs with slotted weights.

A wheel of diameter 2m is shown in figure with axle at O. A force F = 2N is applied at B in the direction shown in figure.

Calculate the moment of force about

(i) the centre O, and

(ii) the point A.

A 50 kg mass is being lifted by using a 1 metre long lever. If the length of the lever is reduced by 20%, how much more or less force is to be applied to achieve the same torque?