Question

An ice block of mass 120g with a shot of lead of mass=2 g frozen in the centre, floats on water, temperature 0 degree celsius, in a closed tank. How much heat (in cal) should be transferred to the ice if we want the block to start sinking? The density of lead is 12 g/cm^3, the density of ice 0.9 g/cm^3, its heat of fusion 80 cal/g.