# Railways NTPC (Technical Ability) Engineering Mechanics and Strength of Materials Engineering Mechanics

Engineering Mechanics

Category : Railways

Engineering Mechanics

• Engineering mechanics is the application of mechanics to solve problems involving common engineering elements.
• The goal of this Engineering Mechanics course is to expose students to problems in mechanics as applied to plausibly real-world scenarios.
• Dynamics all which are all highly applicable in engineering. But the most important part of them is statics (study of body at rest) which is not only a base for all others, but also have the highest engineering application.
• Physics also involve optics, waves, quantum, and relativity theory, which have no fundamental engineering application yet.
• Forces act along the members, and there are no shear forces or moments. A truss is therefore defined as a system composed entirely of two-force members, which only carry axial loads.
• The ends of a truss are pinned, so that they don't carry moments. The only reactions at the ends of a truss member are forces. External forces on trusses act only on the end points.
• Truss problems are solved by the method of sections, where an imaginary cut is made through the member(s) of interest, and global equilibrium of forces and moments are used to determine the forces in the members, or by the method of joints, in which a single join is isolated and analyzed and the resulting forces (not necessarily with a numerical value) are transferred to adjacent joints, where the process is repeated.
• Applied mechanics is a branch of the physical sciences and the practical application of mechanics.
• Applied mechanics examines the response of bodies (solids and fluids) or systems of bodies to external forces. Some examples of mechanical systems include the flow of a liquid under pressure, the fracture of a solid from an applied force, or the vibration of an ear in response to sound.
• A practitioner of the discipline is known as a mechanician.
• Applied mechanics, as its name suggests, bridges the gap between physical theory and its application to technology.
• As such applied mechanics is used in many fields of engineering, especially mechanical engineering. In this context, it is commonly referred to as engineering mechanics.
• Much of modem engineering mechanics is based on Isaac Newton's laws of motion while the modern practice of their application can be traced back to Stephen Timoshenko, who is said to be the father of modern engineering mechanics.
• Within the theoretical sciences, applied mechanics is useful in formulating new ideas and theories, discovering and interpreting phenomena, and developing experimental and computational tools.
• In the application of the natural sciences, mechanics was said to be complemented by .Lewis and Merle Randall, the study of heat and more generally energy, and electro mechanics, the study of electricity and magnetism.
• The current carrying wire wound spirally in the form of helix is known as solenoid or coil.
• When a current carrying conductor is placed at right angle to the direction of magnetic field, a mechanical force is experienced on the conductor in a direction perpendicular to both the direction of magnetic field and flow of current. The direction of this force can be determined by Fleming's left hand rule.
• According to Fleming's left hand rule if the thumb, forefinger and middle finger of the left hand are stretched in such a way that they are at right angles to each other mutually and forefinger points towards the direction of the magnetic field, middle finger towards the direction of the flow of current then thumb will point the direction of force acting on the conductor.
• The magnitude of dynamically induced emf in a conductor moving at right angles to a uniform magnetic field is given as e=B/v volts. If the conductor moves at an angle $\theta$ to the magnetic field, then e = B/v sin$\theta$ volts

The direction of dynamically induced emf is given by Fleming's right hand rule. According to Fleming's right hand rule:

If the thumb, forefinger and middle finger of right hand are held mutually perpendicular to each other, forefinger pointing into the direction of the field and thumb in the direction of motion of conductor then the middle finger will point in the direction of the induced emf.

• The direction of flow of electrons is opposite to that of conventional current.
• The steady flow of electrons in one direction caused by the applied electric field constitutes electric current, called the drift current.
• EMF (electromotive force) is the force that causes a current to flow in an electric circuit while the potential difference between any two points in an electric circuit is that difference in their electrical state which tends to cause flow of electricity from one point to the other.

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##### Notes - Engineering Mechanics

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