How much work can be obtained from 100 calories of heat energy?

A metal block of density 5000 kg/m³ and mass 2 kg is suspended by a spring of force constant 200 N/m. The spring block system is submerged in a water vessel. Total mass of water in it is 300 g and in equilibrium the block is at a height 40 cm above the bottom of vessel. If the support is broken. Find the rise in temperature of water (in ^oC). Specific heat of the initial of block is 250 J/kg K and that of water is 4200 J/kg K. Neglect the heat capacities of the vessel and the spring.