A gasoline engine operates on an Otto cycle and is running at 2000 RPM. At that speed, it has an inlet air mass flowrate of 0.085 kg/s at a pressure of 85 kPa and a temperature of 280 K. After combustion the temperature is 2000 K and the highest cycle pressure is 5 MPa. Find the compression ratio, the cycle efficiency, and the heat added during combustion.

At 12 noon, the count in a bacteria culture was 400; at 4: 00 pm the count was 1200 let p(t) denote the bacteria cou population growth law. find: (a) an expression for the bacteria count at any time t (b) the bacteria count at 10 am. (c) the time required for the bacteria count to reach 1800.

In the winter, in order to keep the classroom steadily at 68 f before 10 pm, heating with an average rate of 42,000 btu/hr is provided. assume the outdoor temperature maintains at 32°f, determine the electrical power (kw) required to (a) operate a reversible heat pump (b) operate a real heat pump with a cop (7) of 4.5 and (c) operate an electrical-resistance heater.

Not a characteristic property of ceramic material (a) high temperature stability (b) high mechanical strength (c) low elongation (d) low hardness