Liquid water is contained in an insulated rigid container. An electrical resistance heater is inside the device, is supplied with 48 volts, and draws 6 amps during operation. A shaft passes through the wall of the container; a propeller located inside the cylinder is mounted on the shaft. The shaft is connected to a motor, located outside the container, that produces 35 Newton-meters of torque and operates at 1800 rpm. Heat is transferred from a high temperature object to the water through a part of the container base that is not insulated. The rate of heat transferred is 225 Watts. What is the rate of change of energy of the water in the container?