View Factor Orientation (or View factor or shape factor) plays an important role in radiation heat transfer. View factor is defined as, "fraction of radiation leaving surface 'i' and strike 'j' ". Summation Rule (View Factor) If there is are similar surfaces 'i' and 'j' , then: Blackbody Radiation Exchange Radiation Exchange between Opaque, Diffuse, Gray surfaces in an Enclosure 1. Opaque 2. Surfaces 3. Two surface enclosure Radiation Shield It is used to protect surfaces from radiation act like a reflective surface. References: Material from Class Lectures + Book named Fundamentals of Heat and Mass Transfer by Theodore L. Bergman + My knowledge. Photoshoped pics are developed. Some pics and GIF from Google. Videos from YouTube ( Engineering Sights ).
If force acting on the body result in some traveled distance, then it is called work.
So, the formula for work done is given by:
The above formula can be written as:
There are three types of work which are described below:
Positive Work → If the angle between force and displacement is acute (0 < θ < 90).
Negative Work → If the angle between force and displacement is obtuse (90 < θ < 180).
Zero Work → If the angle between force and displacement is right (θ = 90).
Work Done By Variable Force:
If there is no constant force applied on an object for work done. The formula for work done by variable force is given by:
Work Done By Constant Force:
If constant force is applied on an object to displace from one point to other point but keep in mind it should be in a straight line. The formula for work done by constant force is given by:
Work Done By Weight:
The work done by an object having weight 'W' moving from 's1' to 's2' under the action of gravity is given by:
Work Done By Spring Force:
If we apply force on spring then it is elongated or compressed by a small distance 'ds'. The work done by the force on the spring in moving it from unstretched position to new final position is given by:
Applying 2nd equation of motion Ft = mat with at = v dv/ds, we get:
Since we know T = 0.5 x mass x square of velocity, so
Principle Of Work & Energy For System of Particles:
Principe of work and energy is applied on:
Enclosed region of space.
Work for which internal forces is zero.
For the system of particles, the principle of work and energy is given by:
There should be no energy loss due to particle interaction.
If there is energy loss → this equation cannot be used.
Types of Forces:
There are two types of forces which are described ahead:
Conservative Forces → If the work done by a force is independent of path followed, then it is called Conservative Forces. For e.g: weight, spring force, etc.
Non-Conservative Forces → Forces for which work done around a path is not zero and is dependent of path followed. For e.g: frictional force, etc.
Gravitational Potential Energy:
Energy due to height is called gravitational potential energy. This energy is given by:
Elastic Potential Energy:
The elastic potential energy (due to compression or elongation of spring) is given by:
Potential Function:
Potential function is the sum of gravitational and elastic potential energy. Its formula is given by:
Conservation of energy means: "Total energy of the system of particles remains constant if only the conservative forces doing work to the system".
Since, considering the work done by non-conservative energy is zero. So:
For the system of particles:
First we will learn statics and dynamics and then we will talk about why we need to learn these?
References:
Material from Class Lectures + Book named Engineering Mechanics Statics & Dynamics by R.C. Hibbeler (12th Edition) + from YouTube channel named Yiheng Wang for Engineering Dynamics Mechanics + my knowledge.
It depends on the scenario when and what equation to use. If there is a force acting on a body and displacement is shown then energy and work principle should be used. If there is a vertical displacement or no contact with horizontal during motion then use energy conservation. ******************************* For momentum and impulse equation: If there are non-conservative and conservative forces bith are present between bodies then use Impulse (Linear or Angular) and momentum principle. If there is only conservative forces present then use momentum conservation. Hope you will find your question's answer.
Reynolds Number: Reynolds Number is the ratio of Inertial forces to the Viscous forces. By knowing this number, one can describe the flow whether the flow is laminar, turbulent or transitional flow. There are three possibilities of the range of Reynolds Number: If Reynolds number < 2100 or 2300 ⟺ Laminar Flow If Reynolds number > 4000 ⟺ Turbulent Flow If 2300 < Reynolds number < 4000 ⟺ Transitional Flow In case of different shapes other than circle, the formula for Reynolds Number remain the same however diameter involves in the formula become Hydraulic Diameter which is given by: For pipe: Critical Reynolds Number ⟾ The Reynolds number at which the flow becomes turbulent Re cr For different shapes, the hydraulic diameters are given by: Completely Filled Flow In Closed Channel: If pipe is is considered to filled completely with closed channel, then following are the conditions which...
Intersection Of Solids: Solids are obtained by the combination of of two or more basic solids. When two or more solids combine, a definite curve/line is seen at their intersection. This curve/line is called curve/line of intersection (COI / LOI) and it is the result of inter-penetration of solids. Applications Of Intersection Of Solids: Designing a sheet metal objects. Automobile Parts. Moulding patterns. Forged end of connecting road. Intersection of two contacting surface, etc. Inter-Penetration Of Solids: When one solids penetrates another solids then their surfaces intersect and at the junction of intersection a typical curve is formed, which remains common to both solids. This curve is called Curve of Intersection and it is a result of inter-penetration of solids. Cases Of Intersection Of Solids: First we need to discuss the general solution steps of how we draw intersection of solids diagram. So know, we are going to discuss the basic steps:...
Types Of Lines And Its Uses: There are three types of types on the basis of thickness and they are: Visible Lines ↝ It represents features that can be seen in the current view. Hidden Lines ↝ It represents features that cannot be seen in the current view. Center Line ↝ It represents symmetry, path of motion, centers of circles,, axis of asymmetrical parts. Dimension and Extension Lines ↝ It indicates the sizes and location of features on a drawing. Placement Of Dimension Lines: Dimension should be outside the view. Dimension should be applied to one view. Dimension should be placed in a view that shows the distance in its true length. Dimension lines should be placed, in general 10 mm (1/2 in) away from the outlines from the view. Parallel lines should be placed uniformly. Values should be midway (auto centered) between the arrow heads, except when a center-line interferes. Dime...
When did i use conservation of energy and when i use principle of work and energy? I mean at what scenario?
ReplyDeleteIt depends on the scenario when and what equation to use.
ReplyDeleteIf there is a force acting on a body and displacement is shown then energy and work principle should be used.
If there is a vertical displacement or no contact with horizontal during motion then use energy conservation.
*******************************
For momentum and impulse equation:
If there are non-conservative and conservative forces bith are present between bodies then use Impulse (Linear or Angular) and momentum principle.
If there is only conservative forces present then use momentum conservation.
Hope you will find your question's answer.