Which of the following processes occurs in a battery? Batteries convert mechanical energy into chemical energy.
Batteries convert chemical energy into kinetic energy.
Batteries convert mechanical energy into electric energy.
Batteries convert chemical energy into electric energy.

The summit of chimborazo, in ecuador, which is at a distance of about 6,384 km from the earth’s center. the bottom of the mariana trench, in the western pacific ocean, which is nearly 6,370 km from the center of the earth. on the surface of earth on the equator line.

Air is contained in a variable-load piston-cylinder device equipped with a paddle wheel. initially, air is at 400 kpa and 17°c. the paddle wheel is now turned by an external electric motor until 75 kj/kg of work has been transferred to air. during this process, heat is transferred to maintain a constant air temperature while allowing the gas volume to triple. calculate the required amount of heat transfer in kj/kg.

4r-134a enters the condenser of a residential heat pump at 800 kpa and 50°c at a rate of 0.022 kg/s and leaves at 750 kpa subcooled by 3°c. the refrigerant enters the compressor at 200 kpa superheated by 4°c determine (a) the isentropic efficiency of the compressor, (b) the rate of heat supplied to the heated room, and (c) the cop of the heat pump. also, determine (d) the cop and rate of heat supplied to the heated room if this heat pump operated on the ideal vapor-compression cycle between the pressure limits of 200 and 800 kpa. (0.757, 4.37 kw, 5.12, 6.18, 3.91 kw)