### Specific Heats of a Gas

The specific heat of a substance may be broadly defined as the amount of heat required to raise the temperature of its unit mass through 1°. All the liquids and solids have one specific heat only. But a gas can have any number of specific heats (lying between zero and infinity) depending upon the conditions, under which it is heated.

Following are the two types of specific heats of a gas :

1. Specific heat at constant volume. It is the amount of heat required to raise the temperature of a unit mass of gas through 1°, when it is heated at a constant volume. It is generally denoted by Cv

Let
m = Mass of the gas,
T1 = Initial temperature of the gas, and
T2 = Final temperature of the gas.

Total heat supplied to the gas at constant volume,
Q = Mass x Sp.heat at constant volume x Rise in temperature
Q = m.Cv(T2—T1)

A little consideration will show, that whenever a gas is heated at constant volume, no work is done by the gas. The whole heat energy is utilized in increasing the temperature and pressure of the gas. In other words, all the amount of heat supplied remains within the body of the gas, and represents the increase in internal energy of the gas.

Note: When the specific heat at constant volume (Cv) is multiplied by the molecular mass of a gas (M), it is called volumetric or molar specific heat at constant volume. It is denoted by Cvm. Mathematically,

Cvm = M.Cv

2. Specific heat at constant pressure. It is the amount of heat required to raise the temperature of a unit mass of a gas through 1°, when it is heated at constant pressure. It is generally denoted by Cp.

Let
m = Mass of the gas,
T1 = Initial temperature of the gas,
v1 = Initial volume of.the gas, and
T2, v2 = Corresponding values for the final conditions of the gas.

Total heat supplied to the gas at constant pressure,

Q = Mass x Sp. heat at constant pressure x Rise in temperature

Q = m.Cp(T2-T1)

Whenever a gas is heated at a constant pressure, the heat supplied to the gas is utilised for the following two purposes :

1. To raise the temperature of the gas. This heat remains within the body of the gas, and represents the increase in internal energy. Mathematically, increase in internal energy,

dU = m.Cv (T2– T1)

2. To do some external work during expansion. Mathematically, workdone by the gas,

W = p (v2– v1) = m.R (T2– T1)

It is thus obvious, that the specific heat at constant pressure is higher than the specific heat at constant volume.

Note: When the specific heat at constant pressure (Cp) is multiplied by the molecular mass of a gas (M), it is called volumetric or molar specific heat at constant pressure. It is denoted by Cpm. Mathematically,

Cpm = M.Cp

### Are Engineers Favourite Among Girls?

What do girls think about men who are engineers and what type of engineers are most favourite among girls? A survey was conducted by a team of aboutmech with members chosen from different countries. Each team member carried out a neutral survey in his/ her country to evaluate what females think about most of the engineers from different engineering branches. An overview of different questions asked in survey is given below:

Question: Which male engineers do you find more attractive as a husband?
Almost 50% women voted for mechanical engineers to be the most attractive husbands among other engineers. So mechanical engineers are most favourite among girls as a husband. They find them more trustworthy, intelligent, and creative. A married women from California said, “If your husband is a mechanical engineer, he will help you in everyday tasks. Because mechanical engineers are good team players and they have creative ideas about everything.”

### Best CV Format for Mechanical Engineers

Fifty percent engineers fail to grab a dream job because of basic faults in their CVs/ Resume. This article tells you about best CV format for mechanical engineers and how you are supposed to design your CV when applying for jobs. You CV is your first impression on future employer. He/ she does not know you. Your CV is the only representation of your personality. He/ she may select or reject you after first glance on your resume.
I have experienced shortlisting and interviewing candidates for different jobs. I was astonished to learn that most of the candidates simply copy paste each others CVs without any changes at all. These types of CVs are rejected immediately. I am not trying to tell you that you should avoid copying, rather i ma telling you to refrain from giving your CV to your friends.
An ideal CV consists of following portions:
Name/ Address of the applicantObjectiveEducation RecordEmployment HistoryProfessional SkillsAwards & AchievementsCo-Curricular Activities/ Inter…

### Engineering Mechanics - Introduction

The Engineering Mechanics is that branch of Engineering-science which deals with the principles of mechanics along with their applications to engineering problems. It is sub-divided into the following two main groups:

(a) Statics, and (b) Dynamics

The Statics is that branch of Engineering Mechanics which deals with the forces and their effects, while acting upon the bodies at rest.

The Dynamics is that branch of Engineering Mechanics which deals with the forces and their effects, while acting upon the bodies in motion. It is further sub-divided into the following two branches:

(i) Kinetics, and (ii) Kinematics

The Kinetics is that branch of Dynamics, which deals with the bodies in motion due to the application of forces.

The Kinematics is that branch of Dynamics which deals with the bodies in motion without taking into account the forces which are responsible for the motion.