A 390 g glass coffee cup is at a room temperature of 20?C. It is then plunged into hot dishwater at 80 ?C. If the temperature of the cup reaches that of the dishwater, how much heat does the cup absorb? Assume the mass of the dishwater is large enough so its temperature doesn't change appreciably and the specific heat of glass is 840 J/kg ·?C. Answer in units of J