A block of iron is suspended from one end of an equal-arm balance by a thin wire. To balance the scales, 8.25 kg are needed on the scale pan at the other end. The density of iron is 7.87×103 kg/m3 and the density of water is 9.98×102 kg/m3
a) What is the volume of the block (in m3)?
b) Next, a beaker of water is placed so that the iron block, suspended as above, is submerged in the beaker but not touching the bottom (see the figure). What mass (in kg) is now necessary to balance the scales?