A heat engine uses a heat source at 730°C and has an ideal (Carnot) efficiency of 26%. To increase the ideal efficiency to 41%, what must be the temperature (in °C) of the heat source?

the area between the graph and the t axis

energy can be converted from one form to another, but it cannot be created or destroyed in ordinary chemical or physical means. do not understand what you are asking but hope this

that would be because of both gravity and friction. so     c