Please find an online chat with a class X student in an attempt to clarify his doubts on Gravitation.
aswinramesh43: gud morn sir
aswinramesh43 is online.
MATHEW: good morning
aswinramesh43: i didnt get any answer from u
aswinramesh43: i have sent u 1
MATHEW: I am getting lot of questions everyday and I find it difficult to answer all instantly.
If it’s urgent now, please ask now
or give me the topic on which you asked
aswinramesh43: i understand sir
its not very urgent
MATHEW: tell, I can look at it now.
aswinramesh43: 1 min sir
MATHEW: Because many questions are already answered at www.askphysics.com in one way or other
aswinramesh43: every planet revolve around the sun . which force is responsible for that .
aswinramesh43: this was my question
MATHEW: I liked it and I was planning to answer it soon
There are some basic things to remember
An object moves in a straight line with uniform speed if no force is acting on it
The planets move around the sun in circular (or elliptical) orbits, changing its linear path everytime because there is a force acting on it
and the force which compells them to go in circular path is the GRAVITATIONAL FORCE
aswinramesh43: does sun have the force
Evry body in this universe
can exert Gravitational force
aswinramesh43: but have any1 checked it out
MATHEW: The planets moving around the sunb is the evidence
There is no effect without a cause.
MATHEW: The Gravitational force is UNIVERSAL
The statement of the universal law of gravitation goes thus
aswinramesh43: but other planets dont have it
MATHEW: “Every object in this universe attracts every other object with a force which is directly proportional to product of their masses and inversely proportional to the square of distance between tem”
All planets, stars,and even gas and dust have it.
aswinramesh43: then why arent the astronouts going
to other planets
MATHEW: After the bigbang (which created the entire universe) the universe contained gallactic clouds of extremely light matter or gas. They were transformed into planets and stras because of GRAVITATION
They are trying to go
We went to moon and to mars
Without gravitational force, how can someone enter into the surface of the planets.
Please take it from me
“Every object in this universe attracts every other object with a force which is directly proportional to product of their masses and inversely proportional to the square of distance between them”
aswinramesh43: but in moon the gravitational force is just 1/6th of the earth
read the statement
aswinramesh43: that was my qstn
MATHEW: There are two thing
The mass and the size
aswinramesh43: i get it now
MATHEW: A massive body will attract more
1 more qstn sir
my physics mam has told that there no atmosphere around a star then how could it burn i mean we see it very bright and shiny ?
MATHEW: Stars do have atmosphere
but moon doesnot have
because the average speed og gas molecules corresponding to the temp of moon is greater than the escape velocity (The minimum speed required for a body to escape from the surface of a body, a planet or a satellite)