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What is motion
The blood is continuously flowing through our arteries and
veins supplying nutrients to various organs and fighting off invaders the earth
has been spinning since time immemorial creating what we call it day and night
but do you know what all these events have in common they are in a state of
movement or motion have you ever imagined what would happen if the aspect of
movement was removed from these events that is if things started moving the
consequences are unimaginable even if we are faced with a traumatic event we
are told to leave the past behind and move on these examples are few of many
that serve to prove the phrase movement is life the different types of motion
in all scenarios are studied by physics to better understand this let us take a
walk in the park while in the park we see a lot of people doing various
activities like walking running playing cycling etc but what are all these
people actually doing and what do all their activities have in common well they
are moving or they are said to be in motion but what is this motion we have all
heard the phrase time and tide waits for none the part of the phrase which says
waits for none indicates that for us to be regular we have to do things on time
in other words we have to move with time this movement with time is called
motion if we pay a little more attention.
We will realize that the phrase is
also a comparison of our Silistra time thus for a body to be in motion it has
to be compared to or related to something hence when we see anything moving we
see that it's in motion and if it's not moving then we usually say that it's
not in motion or stationary but when we call things stationary are they really
stationary these stationary objects are along with us on earth and as we all
know our earth is not only rotating about its axis but also revolving around
the Sun so isn't the earth in motion 24/7 yes it is and technically if the
earth is in motion then anything on it including you me and all those
stationary objects are also in motion so even if these so-called stationary
objects are moving why do they appear stationary to us well just like in life
the philosophy in physics - is the same it's all about perspective the way you
look at things if we consider stationary objects on earth then from our
perspective these objects do not their position because b2 are on earth with
these objects however if we were astronauts and we were to view these same
objects from space then from our perspective these objects would appear to
change their position and now seem to be moving this perspective position or
relative position of an object is called inertial frame of reference so what we
are trying to get at through all this is the fact that the feeling of things
moving and being stationary is because motion is relative.
So now let's keep in
mind that this concept of motion is not limited to objects on earth alone but
also objects beyond it like the solar system and galaxies in space let's
understand this with the situation imagine you and your friend are sitting in a
car which is moving you will notice that your friend is still on not moving but
everything outside the car window is moving behind like this man here but if
you see the same situation from the man's perspective then you would notice
that it's the car that's moving and with it both you and your friend this funny
feeling is because as mentioned earlier motion is relative.
Now let's be a bit observant though objects in the park are in motion either directly or indirectly we notice not all motion of people or objects are the same so now let's understand the different types of motion involved in this situation we can see that the person is jogging on a straight road this type of motion
Which
occurs along a straight line is known as rectilinear motion light from the Sun
lightbulbs and stars always travels along a straight line and hence is the best
example of rectilinear motion now if we consider children playing with the ball
we see that when they throw the ball in air it does not travel along a straight
line but rather takes a curved path this type of motion is known as curvilinear
motion in which a body travels along a curved path can you recognize any other
activities in your day-to-day life which involves curvilinear motion the game
of cricket is a good example when we bat for a six we notice that the ball
follows a curved path as it crosses the boundary now that we know what
rectilinear and curvilinear motion is let's look at the scenario of a race and
see what we can learn from the scenario here we see that there are kids
participating in a race at the end of the race we see that there is a tie
between three kids the reason for the tie was because all three kids took the
same amount of time to complete the race the distance covered is also the same
as it's a fair race thus we can conclude that all three kids took the same time
to cover an equal distance this type of motion we're bodies take an equal amount
of time to cover equal distance is known as translatory motion while looking at
the cycles and the car we see that the tires are moving and their motion is
along an axis such a motion is called a rotatory motion or rotational motion
and sometimes also mentioned as circular motion other examples of circular
motion are the merry-go-round and spinning tops in which both the objects spin
around a particular axis which is at the centre.
Now if we look at another bunch of kids who are swinging we see that they're moving back and forth from a particular point the center this repeated motion of a swing going back and forth is known as oscillatory motion where else can we see oscillatory motion we can see such a motion in the pendulums of clocks such as the grandfather's clock if the rate of oscillation increases rapidly then this motion now becomes vibratory motion examples of vibratory motion are musical instruments such as the guitar violin drums etc another type of motion is periodic motion as the name suggests when a body repeats its motion after regular or constant intervals of time it is known as periodic motion examples include the hands of the clock earth revolving around the Sun and the Halley's Comet which is seen only once in 76 years periodic motion can also be known as uniform motion because the movement is done in equal interval of time with constant speed.
For example if a man covers a constant length of 10 meters for every minute then at the end of 10 minutes he would have covered a total distance of 100 meters this is known as uniform motion as long as this condition is fulfilled the concept of uniform motion can in fact be applied to other types of motion as well so if this type of motion is carried out in a circular path then it is known as uniform circular motion but what if the man is not covering a constant length an equal interval of time say that at times he walks slowly taking more time and sometimes he walks fast taking comparatively a lesser time then these fluctuations of variations decrease the uniformity of motion and hence is known as non-uniform motion this concept too can be applied to other types of motion so what happens if this is carried out in a circular path we get non-uniform circular motion simple isn't it so in this session we saw how important and involved motion is in our life that the concept of motion only comes into effect upon comparison of one body to another body that motion is also of many different types we hope that this session has been informed while arousing your interest.
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