Describe the working of a beam balance.
A beam balance is used to measure the mass. It consists of a horizontal beam, supported at its centre. The beam can move freely about its support and a pointer is attached to the centre of the beam. Two similar pans are suspended at equal distances from the centre of the beam by means of strings of equal lengths. The object whose mass is to be measured is kept on one pan and the standard known masses are kept on the other pan till the beam is horizontal and the pointer is vertical. Then the sum of the known masses gives the mass of the object.
