Internal energy - thermodynamics, Mechanical Engineering

Internal Energy (U):

It is the energy possessed by the system on account of its configurations, and motion of atoms and molecules. Not like potential energy and kinetic energy of a system, which is visible and can be felt, internal energy is the invisible form of energy and can only be sensed. In thermodynamics, the major interest of study lies in knowing the change in internal energy than to know its absolute value.

The internal energy of a system is the sum of energies contributed by several configurations and inherent molecular motions. These contributing energies are given below

(1) Spin energy: because of clockwise or anticlockwise spin of the electrons about their own axes.

(2) Potential energy: because of intermolecular forces (Coulomb and gravitational forces), which keep molecules together.

(3) Transitional energy: because of movement of molecules in all the directions with all possible velocities within the system, this results in kinetic energy acquired by translatory motion.

(4) Rotational energy: because of rotation of molecules about the centre of mass of the system, resulting in kinetic energy acquired by the rotational motion. Such form of energy exists invariably in diatomic and polyatomic gases.

(5) Vibrational energy: because of vibration of molecules at the high temperatures.

(6) Binding energy: because of force of attraction between various sub atomic particles and nucleus.

(7) Other forms of energies such as Electric dipole and magnetic dipole energy when system is subjected to electric and magnetic fields. High velocity energy when rest mass of system mo changes to variable mass m according to Eisenstein's theory of relativity). The internal energy of system can increase or decrease during the thermodynamic operations. The internal energy will increase if the energy is absorbed and will decrease when energy is evolved out.

 

Posted Date: 10/15/2012 1:41:29 AM | Location : United States







Related Discussions:- Internal energy - thermodynamics, Assignment Help, Ask Question on Internal energy - thermodynamics, Get Answer, Expert's Help, Internal energy - thermodynamics Discussions

Write discussion on Internal energy - thermodynamics
Your posts are moderated
Related Questions
Q. What is the basic working of Cooling Tower? Cooling towers are generally located downwind from process units to adequately disperse vapors (from exchanger leaks) and minimiz

Degre e of Super Heat: It is difference between the temperature of superheated steam and saturation temperature resultant to the given pressure. So, the degree of superhea

Throttle Valve: The throttle valves control the quantity of mixture supplied to the cylinder. This is controlled by throttle grip with the help of a cable. When we open throttle

Q. What do you mean by Risers and Downcomers? Risers and downcomers shall be staggered along the shell of the WHB and steam drum for uniform water/steam circulation in the syst

what is the maximum principle stress

Determine the Forces in Members in Roof Truss Determine the forces in members EF, EL, FL, and LK in the roof truss shown below and state whether the members are in tension or

Problems on Structural Design of Combined Footings a. Two columns 50 cm x 50 cm in size support service loads of 1200kN and 800kN.The centre to centre spacing between columns

Present and talk about the bearing, a typical mechanical element for friction decreasing. Complete Table  Q2 about benefits,disadvantages and examples of applications of the follow

An aircraft flap actuator housing made of cast magnesium alloy ZAG3A-T4 with uniaxial yield strength σ Y = 14,000 psi.  At the suspected critical point the calculated state of str

High growth has been observed since 2001-02 in automobile production. Annual growth was 16.0 percent in April-December, 2004; the growth rate in 2003-04 was 15.1 percent (Table 1.