The final answer is -322, 320 Joules. The solution for the problem is:
The equation that must be used in this problem is:
U = mCp(Tf-Ti)
where:
U = energy released or absorbed in Joules
m = mass in kg
Cp = specific heat of material in J/kg-C
Tf = final temperature, C
Ti = initial temperature, C
Looking up the Cp of granite gives a value of 790 J/kg-C.
U = 17kg (790 J/kg-C) (21-45)
U = - 322, 320 Joules (negative means heat is released)