Skip to main content

THE LAZY BODY

  


  Try to move a loose rock.  Try to catch a cricket ball.  Both will be difficult.  Starting a body at rest or stopping  a moving body requires force.  A body always resist the change.  The resistance level is proportional to the mass of the body.  This property of the body is called 'Inertia'.  So we can say mass is the measure of inertia or vice versa.

     In earth, gravitational force acts on all the bodies.  We measure it and call it weight.  In space, in the absence of gravity, pure mass and inertia can be measured using artificial force.



     Once we overcome the 'inertia' (resistance) and start the body, it is easy to keep it going.  That is why, starting of the vehicles and machines requires lot of energy.  The satellites are pushed( by rocket) once into the orbit and it keeps on resolving around the earth for number of years.

    In rotational motions, inertia is not enough.  We have to calculate the "moment of inertia".  It means the rotating mass should be multiplied by the square of the distance between itself(mass) and the axis of rotation.

    In the wheels of the all the vehicles, more mass (Tyre, air) is present on the outer edge-rim.  Hence distance from the axis of rotation increases and the moment of inertia increases.  So the wheels in motion cannot be easily disturbed and this will aid the saving of the fuel.  The inertia-laziness is also useful.

     We, humans also have inertia.  It is difficult to start any work. Once started, it will move on.  So initiate and start the most difficult work tomorrow morning.  It is from human psychology.

Note:  When you travel in a speeding car and the car is suddenly stopped by braking; your body will not be stopped due to inertia.  Hence, you will dash against the dashboard.  To avoid this, wear seat belt ; attach yourself with the car and be a part of the car.   

Comments

Popular posts from this blog

THE EARTH, A SUPER ORGANISM

     JOIN MY COURSE: "Become a programmer in a day with python"       A man called 'love lock' (what a name) proposed a theory called Gaia theory, named after Greek Goddess.      It says, "Earth is a self-regulating organism like a human being.  The organic life in it interacts with in-organic matter and maintains atmosphere, temperature and environment".  Hence the earth is still suitable for the life to thrive.      Imagine, in a particular place, there are lot of flowers.  Some flowers are white and some are darkly coloured.  We know, white reflects light and heat while dark absorbs the same.  White flowers can thrive in hot climate.  But dark flowers requires cold climate.  The absorption and reflection balances and the environment reaches average, warm temperature at which both the flowers can co-exist.  This is the essence of "Gaia" theory.      On our earth, the oxygen constitute 20% of the atmosphere.  The oxygen level is always mai

THE PARABOLA

          A jet of water shooting from a hose pipe will follow a parabolic path.  What is the so special about parabola.    Y= x^2 Draw a graph for the above equation.  It will result in a parabola.  This parabola is also called unit parabola.  Any equation involving square will yield a parabola. Example:  Y = 2x^2 +3x+3 (also called quadratic equation)    X= 2 and -2, both  satisfies the equation 4 = X^2.  Parabolic equations always have two solutions.     Any motion taking place freely under gravity follows parabolic path. Examples:   An object dropped from a moving train,   A bomb dropped from flying plane,  A ball kicked upwards.      If a beam of light rays fall on the parabolic shaped mirror, they will be reflected and brought to focus on a point.  This fact is made use of in Dish Antenna, Telescope mirrors, etc.      Inverted parabola shape is used in the construction of buildings and bridges.  Because the shape is able to bear more weight.      A plane

DISORDER IS THE "ORDER OF THE DAY"

         Imagine a balloon full of air.  The air molecules are moving randomly inside the balloon.  Let us pierce the balloon with a pin.  The air rushes out.  Why should not the air molecules stay inside the balloon safely and ignore the little hole?  That is not the way the world works.  The molecules always "want to occupy as many states as possible".  Hence the air goes out in the open to occupy more volume.   The things always goes into disorder (entropy) and the disorder increases with time.  The above statement is what we call "second law of thermodynamics".      Consider a cup of coffee on the table. Suppose the heat from entire room flows to your cup of coffee, the coffee will boil and the rest of the room will freeze.  Freezing means bringing things to order and arrangement.  It violates the second law.  Hence it will never happen.  Hence heat must flow from high temperature to low temperature and not the other way.        The air molecules in y