Molecular Physics | Thermodynamics Answers

Problem 1.6: A piston-cylinder device contains 0.05 m3 of a gas initially

at 200 MPa. At this state, a linear spring that has spring constant of 150

kN/m is touching the piston but exerting no force on it. Now heat is

transferred to the gas, causing the piston to rise and compress the spring until the volume inside the cylinder doubles. If the cross sectional area of the piston is 0.25 m2, determine the fraction of workdone by the gas against

the spring to compress it.

 2.5g of water at 100K occupies a volume of 2.5cm3 at atmospheric pressure. When the water is boiled, it occupies

4178cm3 as steam. What is the change in its internal energy? The latent heat of vaporization is 2.26106 J / kg. the pressure of one atm is 1.013105 Nm.2 

enthalpy of the steam at the entry of condenser is 200 kilo joule enthalpy of water at the exit of condenseris 100 kj what will be the work done by condensor

In a Stirling cycle, the pressure and temperature at the start of isothermal compression are 1 bar and 40°C. The compression ratio is 7 and the maximum temperature in the cycle is 1200°C. Determine;

i) The maximum pressure and the mean effective pressure

ii) The thermal efficiency of the cycle with and without a regenerator

A backyard swimming pool is 12 feet in diameter and 36 inches

deep. It is filled with water from a hose at 8.0 degrees celcius.

Determine the amount of heat that must be added to the water to

raise the temperature to 28 degrees celcius. The specific heat

capacity of water is 4186 J/kg/C.

If the compressor of example 5.1 is to be driven at 300 rev/min and is single-acting single-cylinder machine, calculate the cylinder bore required, assuming a stroke to bore ratio of 1.5:1. Calculate the power of the motor required to drive the compressor if the mechanical efficiency of the compressor is 85% and that of the motor transmission is 90%. Determine also the isothermal efficiency of the compressor.

If λm for solar radiation is 4573 Ǻ and Wein’s constant b = 2.89 ⨯ 10-3 m – K. calculate the temperature of photo-sphere