Tuesday, 29 October 2013

WEIGHT OF THE EARTH

To begin, let me tell how I got this question? HOW TO DETERMINE THE WEIGHT OF THE EARTH?I and my friend were discussing and he told that there was a post in fb where teacher is  asking the weight of the Earth to the student.So I started to surf on the net.The weight of the earth is approximately about 6 x 1024 Kilograms. After knowing the reason of determining the earth weight , I feel ashamed of India education system as I have completed across these topics and my exposure was very less as I don't have system at home till 12th standard. Now  I will share the answer to you.
THE EARTH














GRAVITATIONAL FORCE


This will be easy for you to understand.Imagine this scenario, step on the weighing machine (scale) in your room and weigh yourself. Now suppose you take the scale, travel to the moon, and stand on it again.The new number will be about 1/6 of what you weighed on Earth. Finally, imagine traveling out into deep space and weighing yourself once more. You will weigh nothing. From this it clearly depicts that weight is variable because weight is a force that depends on something pulling on you. It is the force of gravity, which depends on the mass of the object that is attracting you.

The answer is simply the below equation

where,

G- constant that is 6.67259 x 10-11 m3/kg s2.
F- force of attraction between them.
R- radius of the Earth ( 6,400,000 meters)

Finding a person mass will only involve counting all of the atoms in his body. Now it turns into a complex problem. It turns out that the rate at which an object accelerates due to the force of gravity, called g depends of the mass of the object doing the pulling.

In the case of Earth, we have:

You can now open your room window and take your scale out of the window and count how many seconds it takes to hit the sidewalk. Then measure the distance from your window to the ground, and you can compute the acceleration of the scale. The answer you will get is 9.8 m s-2. Knowing this value of g for Earth's surface, along with the constant G and the 6,731-kilometer distance to Earth's center, you can then calculate Earth's mass to be 6 x 1024 kilograms.
            From this you can calculate the mass of the Earth.


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Saturday, 19 October 2013

KERS

I am a big fan of  Fernando Alonso who is a Formula one Spanish driver.I love him as he drives fast and efficient.So, I want to share a technology used in F1 which is related to power generation.All of you are interested in renewable power generation like Solar ,Wind,etc.The energy that is used in the F1 is also Eco-friendly one.The technology name is KERS.I will also explain its working.Mostly, the sport becomes popular if you mix technology in it.As F1 is the most popular sport which has fans worldwide. I want to share a knowledge on this technology.
KERS ENABLED F1 CAR



LOGO
Generally, in F1(formula one) a car with most prominent aerodynamics model can have the potential to win the title. Other than the aerodynamics model there is a technology named KERS 


KERS- The acronym KERS stands for Kinetic Energy Recovery System. The device recovers the kinetic energy that is present in the waste heat created by the car’s braking process. It stores that energy and converts it into power that can be called upon to boost acceleration .

WORKING

There are basically two types of system-Electrical (battery) and Mechanical (flywheel). Most of the F1 teams have opted for battery i.e., electrical system.


ELECTRICAL SYSTEM WORKING
ELECTRICAL SYSTEM

Electrical system involves the use of the motor-generator set which is incorporated in the car’s transmission and it converts mechanical energy into electrical energy and vice versa.Once the energy has been harnessed it is stored in a battery and released when required.











MECHANICAL SYSTEM
MECHANICAL SYSTEM WORKING

The mechanical system captures breaking energy and use it to turn a small flywheel which can spin at up to 80,000 rpm. When extra power is required, the flywheel is connected to the car’s rear wheels.



When we compare the efficiency of both these systems,Mechanical system is more efficient as it does not changes the state.

There is one more option available - HYDRAULIC KERS, where braking energy is used to accumulate hydraulic pressure which is then sent to the wheels when required.

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Friday, 18 October 2013

CURVE NEGOTIATION



Yesterday, I was reading Hindu newspaper there is a science & tech area where every Thursday QUESTION CORNER will be asked and answer will be provided.This time the question is based on physics.So I want to share to my readers.Here is a question,Why is it difficult for a huge truck speeding at 50 km/hr to negotiate a curve rather than a motorcycle at the same speed although the radius of the banking is independent of mass?and this question also can also be put as How to avoid skidding? 
I know the answer a little bit but not clear.So I want to share the answer for you.I am a big fan of MOTO GP and I love the cornering of Marc Marques.So I have just attached a photo of his cornering to understand my question.Take a look at the answer also.
MARC MARQUES CORNERING

CENTRIPETAL FORCE-  Any motion in a curved path represents accelerated motion, and requires a force directed towards the center of curvature of the path.
CENTRIPETAL FORCE
SUPER-ELEVATION

Whenever a body is negotiating a curved path, an outward horizontal force known as Centripetal force acts on the body.

That is why when we travel in a bus or a train, we feel we are pushed out while traveling in a curved path.To counter-act this force,outer edge of the road or rail is raised slightly in relation to the inner edge or rail.


DIAGRAMMATIC REPRESENTATION
This is known as Super-elevation in case of road and cant in case of railway track. The lifted edge in the road makes thee vehicle to tilt in side i.e., towards the center of the curve because of which a component of the weight of the vehicle will be equal to W.sinθ where θ is the angle through which the outer edge or rail is lifted and acts against the Centripetal force and skidding of the vehicle is prevented.


 In case of a motorcycle, the rider tilts the bike unconsciously towards inside while running on a curved path.However, in case of a truck, it is not possible to do so except the vehicle is tilted slightly equal to the super-elevation in the road.

This makes a large four-wheeled vehicle difficult to negotiate a sharp curve at high speed.

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Thursday, 17 October 2013

TUBELIGHT

When you switch on your tube-light, you may wonder if the switch is on the circuit gets closed and the light glows.But this not a fact.Now I shall explain the working of the tube-light.


TUBE-LIGHT
FITTINGS













STARTER
   The tube-light consists of mainly two parts :
  • Starter-small cylindrical shaped.
  • Choke -large square shaped also known as Ballast.
    CHOKE

      To understand the working of the tube-light,we must refer the circuit diagram.The basic circuit  
      diagram is shown below.
    CIRCUIT DIAGRAM
    PRINCIPLE:

    The choke is a large inductor and it consists of a long copper winding over iron lamination. An inductor by nature has a tendency to throw back the stored current in it, every time the power through it is switched OFF.This principle is used in lighting a fluorescent tube light.


    BALLAST INNER VIEW


    STEP 1: When an AC voltage is applied to a tube light fixture, the voltage passes through the choke, the starter, and the filaments of the tube.
    STEP 2: The filaments light up and instantly warm up the tube. The starter holds the current for a moment and then releases to break the circuit.
    STEP 3: This forces the choke to kick back it’s stored current, which again passes through the filaments and ignites the tube light.
    STEP 4: If the tube does not sufficiently charge up, subsequent kicks are delivered by the choke due to rapid switching of the starter, so that finally the tube strikes.



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    Friday, 11 October 2013

    BALL POINT PEN--- No Substitute INVENTION


    I usually don't take pen to my college .I will borrow from my friend.Yesterday, I borrowed a ball-point pen and it has no cap.I took it to the hostel by keeping it in my pantaloons.To my bewilderment,the ink has leaked and ruined my pants.At that moment,I started wondering why the ball-point pen gets leaked?I have carried pens from my school days and it has not leaked.So i started thinking.
    I browsed the net and I was keen to know the working of the ball-point pen and also I want to know why doesn't all the ink is flowing out.To know answers for these question take a detailed look of the answer.

    GRAVITATIONAL FORCE AND BALL DESIGN


    Even though it is a generation which uses cellphones and e-mails there is no substitute for the pen and paper.These two things are necessary in our evolving day to day life.
    BALL POINT PEN

    REED PEN WITH THE INK
    A pen is a tool used for writing and drawing with a colored fluid- i.e., ink.The ball point pen uses a rotating ball which is made up of brass,steel or tungsten carbide .Thus the name ball point.The ink gets diffused as you use the pen.
    The ball point pen got very popular and it was noticed at the time of inventing this .It is very different
    than its pen predecessors -- the reed pen, quill pen, metal nib pen, and fountain pen.The pens that preceded the ball point pen uses capillary action.

    The problems with this technology are:

            The ink can flow unevenly.  
            The ink is slow to dry.  

    ROAD TO INVENTION: 


    LASZLO BIRLO
    Hungarian journalist Laszlo Biro was well aware of the problems with normal pens. Biro believed that the idea of a pen using a quick-drying ink instead of India ink came to him while visiting a newspaper.  The newspaper's ink left the paper dry.To avoid clogging , he proposed a tiny metal  ball that rotated at the end of
    a tube of this quick drying ink. 

    The ball performs two functions:

           It would act as a cap to keep the ink from drying.
          It would let ink flow out of the pen at a controlled rate. 

    WORKING:


    The key to a ballpoint pen is, of course, the ball. This ball acts as a buffer between the material you're writing on and the quick-drying ink inside the pen. The ball rotates freely and rolls out the ink as it is continuously fed from the ink reservoir.


    The ball is kept in place between the ink reservoir and the paper by a socket and while it is in tight, it still has enough room to roll around as you write. As the pen moves across the paper, the ball turns and gravity forces the ink down the reservoir and onto the ball, where it is transferred onto the paper. It's this rolling mechanism that allows the ink to flow onto the top of the ball and roll onto the paper you're writing on, while at the same time sealing the ink from the air so it does not dry in the reservoir.

    In the case of ballpoint pen ink, the ink is very thick and quick-drying. It is thick so that it doesn't spill out of the reservoir, but thin enough that it responds to gravity. That is why a normal ballpoint pen cannot write upside-down it needs gravity to pull the ink onto the ball and the ink doesn't flow back.


    Because the tip of a normal ballpoint pen is so tiny, it is hard to visualize how the ball and socket actually work.One way to understand it clearly is to look at a bottle of roll-on antiperspirant,
    which uses the same technology at a much larger scale.
                                    
    ANTIPERSPIRANT MODEL
    SOCKET
    HOW THE BALL FITS INTO SOCKET
                                                          
    The ballpoint pen is aptly named because the ball at the tip is the most important part of the pen.  If the ball is held in place to tightly you won't get smooth lines.  If the ball is held in place to loosely you'll get extra ink on the page.If that ball falls out completely then nothing will be holding the ink in at all and you'll get a great flood of ink in your pocket and so when there is a leakage of pen it tells the quality of pen.
    When there is no cap. the movement of ball is not restricted so that ink gets leaked on the pants.When you close your cap ,the movement of ball is restricted and thus leakage problem is so less. 
      
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