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centripetal force  escape velocity  escape  force  great enlightenment  great  object orbits  object  spirit great  velocity  yew posting
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# Comments on My Little Moments: Zero Gravity (2)

Updated: 2018-04-12T16:31:40.626+08:00

Shou Farn: Hah you quoted that line too when I was...

2007-11-11T20:45:00.000+08:00

Shou Farn: Hah you quoted that line too when I was writing about the same topic in ReCom! :D It's indeed a great quote, by the way, as it captured the whole essence of an orbit.

Sophisticatedsoul: Glad that you liked it.

Eric Fu: Thanks for your mathematical comment Professor Fu! :P You and your LaTeX notations, hah. :P

Thank you Mr. Yew, for posting such a informative ...

2007-11-05T03:13:00.000+08:00

Thank you Mr. Yew, for posting such a informative and enlightening blog post!

It has been a while since I last look at physics from the window of intuition - what I have been doing in upper level physics courses are calculations that can be too cumbersome at times.

This post certainly reminds me of the notion of "orbiting" and "escape velocity." I was very intrigued by the idea of escape velocity when I learned it in high school - as long as you throw an object at a speed higher that the escape velocity (I think it is about 11km/s, if my memory serves me right). Attaining the speed of 11 kilometers per second is just like getting from Taman Aman (my neighborhood) to Keat Hwa (my high school) in one second. Sounds impossible...

When an object orbits around the earth, it experiences a force called the centripetal force that maintains the circular motion. For the mathematically inclined, the centripetal force is provided by the gravitational force, i.e.

\frac{mv^2}{r}=G\frac{Mm}{r^2}.

Solving for v,

v=\sqrt{\frac{GM}{r}}.

This gives us the velocity of the object that orbits around the earth at a distance r from the center of the earth.

Great enlightenment! ;)

2007-10-29T12:28:00.000+08:00

Great enlightenment! ;)

In spirit of the great Douglas Noel Adams, as expl...

2007-10-29T08:47:00.000+08:00

In spirit of the great Douglas Noel Adams, as explained by Ford Prefect,

"The secret of flight is to throw yourself at the ground and miss."