Two point charges q, +4.60 nc and 02--2.90 nc are separated by 45.0 cm. (a) what is the electric potential at a point midway between the charges? (b) what is the potential energy of the pair of charges? what is the significance of the algebraic sign of your answer? o positive work must be done to separate the charges. o negative work must be done to separate the charges.

An ideal otto cycle has a compression ratio of 8. at the beginning of the compression process, air is at 95 kpa and 27°c, and 750 kj/kg of heat is transferred to air during the constant-volume heat-addition process. assuming constant specific heats at room temperature, determine (a) the pressure and temperature at the end of the heat-addition process, (b) the net work output, (c) the thermal efficiency, and (d) the mean effective pressure for the cycle. (4390 kpa, 1730 k; 423 kj/kg; 56.4%; 534 kpa)