To practice Problem-Solving Strategy 20.1 Heat Engines. Steam at a temperature TH = 255 ∘C and p = 1.00 atm enters a heat engine at an unknown flow rate. After passing through the heat engine, it is released at a temperature TC = 100 ∘C and p = 1.00 atm . The measured power output P of the engine is 460 J/s , and the exiting steam has a heat transfer rate of HC = 2000 J/s . Find the efficiency e of the engine and the molar flow rate n/t of steam through the engine. The constant pressure molar heat capacity Cp for steam is 37.47 J/(mol⋅K) .

Electric field of the earth. the earth has a net electric charge that causes a field at points near its surface equal to 150 n> c and directed in toward the center of the earth. (a) what magnitude and sign of charge would a 60-kg human have to acquire to overcome his or her weight by the force exerted by the earth’s electric field? (b) what would be the force of repulsion between two people each with the charge calculated in part (a) and separated by a distance of 100 m? is use of the earth’s electric field a feasible means of flight? why or why not?

This energy transformation diagram represents the energy of a skateboarder moving along a half-pipe. as she skates toward the top of the half-pipe, her original kinetic energy is converted to potential energy and friction. how much of the energy is potential?

Can you receive a shock severe enough to prevent you from releasing the wire from an ordinary outlet with dry hands? a. no b. yes explain