Molecular Physics | Thermodynamics Answers

Assume 5 lb/sec of fluid enter a steady state, steady flow system with p1 = 100 psia, 1 =

0.2 lb/ft3

, v1 = 100 fps, u1 = 800 Btu/lb and leave with p2 = 20 psia, 2 = 0.05 lb/ft3

, v2 = 500

fps, u2 = 780 Btu/lb. During the passage through the open system, 10 Btu/lb of heat is

rejected. Find the work in hp.

A steady flow, steady state thermodynamic system receives 45 kg/min of a fluid at 207kPa

and discharges it from point 24 m. above the entrance section at 1034 kPa. The fluid

enters with a velocity of 36.6 m/s and leaves with a velocity of 12 m/s. During this process,

there are supplied 7 kW of heat from an external source, and the increase in enthalpy is

4.6 kJ/kg. Determine the work in kW and in horsepower.

Steam enters a turbine stage with an enthalpy of 3628 kJ/kg at 70 m/s and leaves at the

same stage with an enthalpy of 2846 kJ/kg at 124 m/s. Calculate the work per kg done by

the steam.

Steam with a flow rate of 1360 kg/h enters an adiabatic nozzle (adiabatic, Q=0) at 1378

kPa, specific volume of 0.147 m3

/kg, and specific internal energy of 2510 kJ/kg. The exit

conditions are 137.8 kPa, 1.099 m3

/kg specific volume, and 2263 kJ/kg of specific internal

energy. Find the exit velocity.

In a steady flow apparatus, 135 kJ of work is done by each kg. of fluid. The specific volume,

pressure, and velocity of the fluid at the inlet are: 0.37 m3

/kg, 600kPa, and 16 m/s. At the

outlet are: 0.62 m3

/kg, 100 kPa, and 270 m/s. The inlet is 32 m. above the discharge line.

The heat loss between the inlet and discharge is 9 kJ/kg. In flowing through this apparatus,

does the specific internal energy increases or decreases?

Air flows steadily at the rate of 0.5 kg/s through an air compressor, entering at 7 m/s, 100

kPa, 0.95 m3

/ kg specific volume, and leaving at 5 m/s, 700 kPa, and 0.19 m3

/kg specific

volume. The internal energy of the air leaving is 90kJ/kg greater than that of the air

entering. Cooling water in the compressor jackets absorb heat from the air at the rate of

58 kJ/s. Calculate the work.

An elevator in on the thirtieth floor of an office building when supporting cables shears.

The elevator drops vertically to the ground where several springs absorb the impact of the

elevator. The elevator mass is 2500 kg and it is 100 m. above the ground. Determine: a)

the potential energy of the elevator before its fall, b) the velocity and kinetic energy the

instant before the impact.

A closed system containing a gas expands slowly in a piston/cylinder from 600kPa and

0.1 m3

to a final volume of 0.5 m3

. Determine the work done if the pressure distribution

is determined to be: a) Pv = C, b) pV1.4 = C, c) P = C,

d) p = -300V + 630 kPa where V is in m3

Many gas appliances such as ovens and heaters use a small flame to ignite the main burner .In order to make sure that the small flame is burning, a temperature-measuring device is inserted into the flame. What is the most suitable device to use?

You are asked by your mother to cook pork nilaga. You have only an ordinary ketttle to use for cooking.she even reminds you to save energy because we are in a state of pandemic due to covid -19. Saving resources nowadays is a must because we are not sure of the worl's economy.As a student of Physical Science and with your knowledge of properties of matter in relation to intermolecular forces, how are you going to perform your task in sucb a way that energy in not wasted?