Molecular Physics | Thermodynamics Answers

11. A solid gold vase of mass 20.0 kg is suspended by a rope at sea bottom. What is the Buoyant Force of the seawater on the vase? 

a lump of steel weighing 30kg at a temp of 427 degree celcius is dropped into 150kg of oil at 27 degree celsius. The specific heat capacity of the steel and the oil are 0.47 KJ/KgK and 2.5 KJ/KgK

Activity:

0.01 kg of a certain perfect gas occupies a volume of 0.003m3 at a pressure of 7 bar and a temperature of 131°C. Calculate the molar mass of the gas. When the gas is allowed to expand until the pressure is 1 bar the final volume is 0.02m3. Calculate the final temperature.

A quality governed four stroke, single cylinder gas engine has a bore of 146 mm and a stroke of 280 mm. At 475 rev/min and full load the net load on the friction brake is 433 N, and the torque arm is 0.45 m. The indicator diagram gives a net area of 578 mm2 and a length of 70 mm with a spring rating of 0.815 bar per mm. Calculate the indicated power, the brake power and the mechanical efficiency.

What is the total charge output of the circuit below? 6F 3F CHE 12 F 6F 12 volt

Name the main features of a Carnot cycle

0.5 kg of air executes a carnot cycle having a thermal efficiency of 50%. The heat transfer to the air during the isothermal expansion is 40 kJ. At the beginning of the isothermal expansion, the pressure is 7 bar and the volume is 0.12 m3. Determine:

i) The maximum and minimum temperature of the cycle in K.

ii) The volume of air at the end of isothermal expansion.

iii) The work and heat transfer for each of the four processes.

The following data refer to a four cylinder internal combustion engine operating on a four stroke cycle at 4400 rev/min: volume compression ratio 7.6:1; cylinder diameter 78mm; stroke 105mm; brake power 38 kW; indicated power 47.5 kW; air consumption 21 kg/kg fuel; fuel consumption 13.6 kg/hour; energy release of 1 kg of fuel, 41800 kJ. Determine,

(i) the mechanical efficiency

(ii) the mean effective pressure

(iii) the volumetric efficiency (referred to 1 atm = 1.01325 bar, 0°C)

(iv) the brake thermal efficiency

(v) the brake thermal efficiency ratio relative to the air-standard cycle.

Assume R = 0.287 kJ/kg K.

In a single-acting two-stage reciprocating air compressor 4.5 kg of air per min are compressed from 1.013 bar and 15°C through a pressure ratio of 9 to 1. Both stages have the same pressure ratio, and the law of compression and expansion in both stages ispv^1.3=c . If intercooling is complete, calculate the indicated power and the cylinder swept volume required. Assume that the clearance volumes of both stages are 5% of their respective swept volumes and that the compressor runs at 300 rev/min.