A piece of copper is heated to 90°c and then lowered into a beaker of water which is at 20°c....

A piece of copper is heated to 90°c and then lowered into a beaker of water which is at 20°c. The copper transfers 3040 J of energy to the water before it is removed. The temperature of the copper after it is removed is 50°c. The specific heat capacity of copper is 380 J/kg°C. 

Calculate the mass of the the copper.