Calculate the time taken for 1000L of water at rtp to be heated to 40degrees celsius using a 40kW heater

First the starting parameters of the fluid should be calculated, so at rtp the density of water is 1kg/L therefore mass is 1000kg and the temperature is 20 degrees C. The next step would be to plug these values into Q=mc(t2-t1), as we are given Q, m, and c is 4200J/KgK the change in temperature can be calculated from Q/mc = 0.0095degrees celsius. As the figure given is in watts this is therefore the temperature change per second, therefore the overall change divided by the change per second will give the overall time required which is 2100 seconds or 35 mins.