Uniform Motion

Introduction to Uniform Motion

A motion is said to be uniform if the particle covers equal distances in equal intervals of time, however  small these intervals of time may be , always in the same direction. Strictly speaking , no motion is uniform.

When a particle has uniform motion, neither the magnitude nor the direction of velocity changes , so the velocity is constant in uniform motion and is equal to Instantaneous velocity of the particle. I like to share this equation for frequency with you all through my article.

So uniform is a relative concept. If an object A is in uniform motion relative to another object B, then from B's view there appear to be no force applied to A; i.e. it appears to be neither accelerating nor decelerating, nor changing directions or moving in a curve. The same should apply vice versa.

when a particle possess uniform motion, it's velocity- time graph is a straight line parallel to time axis.If the velocity of the particle is taken as positive, the straight line is taken above the time axis and if it is negative, then the V-t graph will be a straight line below the time axis


Uniform Motion : Velocity- time Graph


The Velocity- time graph for uniformly accelerated rectilinear motion is straight line sloping upwards.

The velocity- time graph for a uniformly retarded motion is a straight line sloping downwards.

Let us consider a particle moving with constant acceleration .If U and V be the velocities at time t1 and t2  respectively, then

`V= U+at` gives the equation connecting initial velocity, final velocity, acceleration and time. I have recently faced lot of problem while learning Effects of Radiation on Humans, But thank to online resources of math which helped me to learn myself easily on net.


Uniform Motion : V-t Graphs and Acceleration


The Velocity- time graph for the uniformly accelerated motion of a particle is a straight line sloping upwards.

The area under the V-t graph gives the distance covered by the particle.It is calculated by the equation `V^2= U^2+2ad`

so here distance is as area under Velocity- time graph

The slope of the V- t graph for uniformly accelerated motion gives the acceleration.

Laser Cutting Process

Introduction to laser cutting process:

Laser which stands for Light amplification by stimulated emission of radiation.When electromagnetic radiation or some times visible radiations  released by the stimulated emission then this is known as Lasers.Electrons present in the elements can change their state in order to attain stability.When any energy is supplied then electrons are excited to higher states,but at the higher states these are not so stable so it jumps down by releasing some energy.These energy comes under certain range .It can be in the electromagnetic range,visible range or may be in some other range of the spectrum.Laser is a monochromatic and short wavelength rays.These rays have high frequency. Is this topic Definition Kinetic Energy hard for you? Watch out for my coming posts.

Laser beams are very useful in many fields.Laser cutting is also a field where lasers are used to cut the materials.Lasers are very high power beams when it is subjected to the materials then material melts,vaporises or burns,or it is blown away by the high pressure beams.As compared to the mechanical cutting this process of cutting is very effective and accurate.Some times materials are very hard to cut by using normal mechanical methods,so in these cases laser cutting  helps and it makes the cutting very easy and simple.

Types of Laser

There are mainly three types of laser cutting device is used depending upon the material used for the production of lasers.These materials are.

1)Carbon Dioxide

2)Neodymium

3)Neodymium yttrium Aluminium garnet

These different lasers are used in different applications.These are used for cutting,trimming,scribing.engraving etc.To produce the laser beams the lasing materials are stimulated ,then the generated beam is reflected so many times internally by using mirrors till it gains high  energy  to come out as monochromatic beams.



Different Methods of Cutting by Laser

By using laser cutting of material can be done in various ways.The high energy of the beam is mainly used to cut the material.Some of the methods are described below

By vaporising-in this method the material is heated to its boiling point to obtain a gap.

Thermal stress cutting-This method is used for the brittle material .When Brittle material is subjected to high heat then it results in crack.

melt and blow-In this method first the material is melt and then it is blown by high pressure beams.

By cold cutting

Scribing

General Electric Refrigerator

Introduction to General Electrical Refrigerators:
A refrigerator is a cooling apparatus. The common name which we use is Fridge. Cooling apparatus is in the sense it is used to cool the products. Mainly it is used for the storage of food devices. This devise is used to reduce the rate of spoilage of food stuffs. The refrigerator keeps a temperature a few degrees above the freezing point of water. It is also called as Freezer. Having problem with What is Electric Charge keep reading my upcoming posts, i will try to help you.

Types of Refrigerators:

1. Absorption Refrigerator – In this quite running is required. They don’t have bulky mechanism.

2. Compressor Refrigerator – They make noticeable noise.

3. Solar Refrigerator – They are designed to reduce electrical consumption .these have advantages that they do not use refrigerants that are harmful to environment.

Non food use: They are used in laboratories, for storing samples analysis, storing film stock and morgues.

Freezer: Freezer units are used in households and in industry and commerce. Domestic freezers are generally upright units resembling refrigerators.

4. Magnetic Refrigerator – These Refrigerators work on the magneto caloric effect. The cooling effect is triggered by placing a metal alloy in a magnetic field.

Temperatures zones and rating:

Some refrigerator are having are having four zones to store different types of food.

1.  -18^0 C (-0^0 F) (freezer)

2.  0^0C (32^0 F) (meats)

3.  5^0 C (41^0 F) (refrigerator)

4.  10^0 C (50^0 F) (vegetables)

The capacity of a refrigerator is measured in either litters or cubic feet.  Typically the volume of a combined fridge-freezer.is split to 100 liters (3.53 cubic feet) for the freezer and 140 liters (4.94 cubic feet) for the refrigerator, the values are highly variable. Please express your views of this topic Temperature Formula by commenting on blog.

Features of General Electric Refrigerator:

The newer refrigerators m y includes:

A powerful failure warning

Chilled water and ice available from an indoor stations o the door need not be opened.

Automatic defrosting.

Automatic cooling at the steam

Inductors in Ac Circuits

Description of an inductor:

An inductor in a AC circuit is a component that has the property of inductance. Inductors have very wide applications. The inductance of an inductor makes the current to lag the voltage in an AC circuit and this phenomenon is used in certain applications. The inductors are also called reactors, chokes and coils depending upon the application. I like to share this formula celsius to fahrenheit with you all through my article.

The inductor is basically a closely wound coil around a material of high permeability (magnetically susceptible).

Let us study what exactly are the functions of inductors in AC circuits.

Concept of Inductance by an Inductor in Ac Circuits:

The above diagram shows a AC circuit connected to an inductor. When an AC voltage is applied to an inductor, the rate of change in current passes through that induces an emf, as per Faraday’s law. This emf, as per Lenz’s law opposes the change in current.

The inductance of an inductor is denoted by L and its unit is Henry, named after the American scientist who discovered electromagnetic induction at the same time with the great scientist Michael Faraday from England.

One unit of Hendry produces an emf of 1 volt for a change in current of 1 ampere per second. Understanding An Electric Current is Measured in Units of is always challenging for me but thanks to all math help websites to help me out.

Inductors in Ac Circuits:

Inductors in AC circuits, as explained earlier opposes the change in current. In a way it can be termed as a magnetic resistor. Like resistors, the equivalent inductance of various inductors is the sum of the values of all the inductance values when they are connected in series. That is,

L = L1 + L2 + L3 ….. + Ln

Similar to the case of resistors, in parallel operation,

(1/L) = (1/L1)+ (1/L2) + (1/L3) ….. + (1/Ln)

Like resistors in resistive circuits, the inductors in AC circuits converts the electrical energy but stores that in the magnetic field.  The energy stored is given by,

E = (1/2) LI^2

Right Angle Mirror

Introduction to right angle mirror:

Any smooth polished surface, which can return the rays of light into the same medium, is called mirror. Looking glass is the best example of mirror. Any highly polished metal surface also acts as a mirror. Still water or oil have a smooth surface and hence acts like a mirror. Even highly polished furniture or the utensils acts like a mirror. Here we discuss the right angle mirror. I like to share this equation for converting celsius to fahrenheit with you all through my article.

Right Angle Mirror

If the two mirrors are arranged so that they inclined at an angle of 90° to each other are called the right angle mirrors. Mirrors are based on the optical phenomenon called reflection. When a ray of light traveling from one optical medium to another optical medium it bounces back from the interface with the change of the angle is called reflection. We can see our image in the looking glass due to the phenomenon of reflection of the light falling on us. Now let us consider that the two plane mirrors M and N are placed at right angle to each other as shown in the diagram.

Let them intersects at point O. Now an object is placed between the mirrors. We get three images of this object. As we know that the number of images formed by the mirrors which are inclined at an angle `theta`° is given by 360 / `theta` - 1 (if 360 / `theta`  is an even number). So, we get the three images formed by this system of the mirrors.
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Conclusion for the Right Angle Mirrors

Here we conclude that the images formed by the system of the right angle mirrors is virtual that means we cannot get these images on the screen. The size of the images is same as that the object. The image formed is laterally inverted. The system of the right angle mirrors are used in the solar cookers, kaleidoscopes, periscopes etc. Generally, we use two plane mirrors to make the right angle mirror system but in the different condition and for the several purposes we use the combination of the plane and spherical mirrors.

Speed Practice Problems

Speed of an object is defined as the distance covered by it in per unit time interval. It is obtained by dividing the distance covered by the object by the time it takes to cover that distance.

Therefore ,                                    Speed = Distance covered / Time taken

The speed practice problems can be solved by using the above formula.

Here are some of the speed practice problems:

Speed Problems

Problem:  A train crosses a pole in 15 seconds. If the length of the train is 300 meters, find the speed of the train. (Answer: 20 m/ sec).

Solution : Speed = Distance / time

Speed =  300 / 15

Speed = 20 m / sec is the answer.


Practice Problems on Speed.

Problem: Brittany walking at a speed of 20 km/h reaches her college 10 minutes late. Next time she increases her speed by 5 km/h, but finds that she is still late by 4 minutes. What the distance of the college from her house?(Answer: 10 km).

Problem: The average speed of Ryan for a 6 hrs journey is 45 km/h. If he travels with the speed of 40 km/h for the first four hours , find the average speed for the last two hrs.

Problem: X and Y are two stations 600 km apart. A train starts from X and moves towards Y at the rate of 25 km/hr. Another train starts from Y at the rate of 35 km/hr. How from X they will cross each other? (Answer: 250km)

Problem: The boat goes 15 km upstream in 80 minutes. The speed of the stream is 5 km/h. What is the speed of the boat in still water? (Answer: 16.25 km/hr)

Problem: A motorboat whose speed in still water is 15 kmph goes 30 km downstream and coves back in a total 4 hours and 30 minutes. Determine the speed of the stream. (Answer : 5 kmph)

Problem:  Alex average speed for the 5 hours is 10 miles per second. His average of the next three hours is 15 miles per hour. Find the average speed for the total 8 hours. (Answer: 11.87 miles per hour).

Demagnetization

Introduction to demagnetization:

The reverse process of magnetization in which a magnet loses part or whole of its magnetism is called demagnetization. Not only magnets or magnetized pieces of iron, but also the unmagnetised pieces of iron are constituted of molecules that themselves are magnetic character. Each molecular magnet possesses a north pole and a south pole. The reason why an unmagnetised pieces of iron does not exhibit magnetic properties although it itself is made up of magnets is that different molecular magnets form closed group so that the effect of the north pole of one of the molecular magnets on a neighbouring molecular magnet is exactly counterbalanced by the opposite pole of the other molecular magnet situated very closed to it.

Methods of Demagnetization

1.Rough handling: it is observed that if a magnet is subjected to rough treatment such as dropping from a height or hammering then it gradually loses part or whole of its magnetism.

The rough handling disturbs the alignment of some of molecular magnets so that the magnetization would become weak.

2. Heating: A magnet is found to lose its magnetism when heated. The quantity of magnetism lost would depend on the temperature to which it is heated. On heating a magnet, the internal energy of the molecular magnets increases. This results in more violent vibrations of the molecules, so that their alignment in a given direction is disturbed and the magnetization becomes weak.

Special Cases of Demagnetization

Electrical method: A long coil (solenoid) of insulated copper wire is connected to a source of alternating current. The magnet is placed inside this coil so that the magnet is along east-west direction. The current is switched on and the magnet is pulled out of the coil. When checked the magnet is found to possess no magnetism.

Self-demagnetisation: It is observed that the magnets lose their magnetism of their own accord.