An inventor claims to have developed a wonderful new heat engine that operates with a relatively cool (and therefor nonpolluting) flame at 190 degrees celcius, and discharges waste heat to the environment at 20 c. his promotional literature advertises that 45 percent of the fuel energy is converted into useful work. calculate the maximum efficiency that can be expected for such an engine. (if your answer is 45 percent, enter .45) (is he scamming you or not? )

The lid of a pressure cooker forms a nearly airtight seal. steam builds up pressure and increases temperature within the pressure cooker so that food cooks faster than it does in an ordinary pot. the system is defined as the pressure cooker and the water and steam within it. if 2.0 g of water is sealed in a pressure cooker and then vaporized by heating, and 5655 j must be added as heat to completely vaporize the water, what is the change in the system’s internal energy? answer in units of j.