Math Is Fun Forum

MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,713

Gravity

A new page on Gravity

Would value your feedback.

Any ideas on how to best present space-time curvature will be welcome!

Also help in tightening up the wording is welcome, too.

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"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,403

Re: Gravity

Hi MathsIsFun,

The page on Gravity is very well made.

The units of 'g' and 'G' in other systems (other than SI), whether they are scalar or vector, and affect on Altitude and Latitude may be included.

The presentation is flawless.

Great work!

Last edited by Jai Ganesh (2016-04-13 21:11:56)

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It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Gravity

Hi MIF;

Any ideas on how to best present space-time curvature will be welcome!

That is the standard way to illustrate space-time curvature. Sometimes, you see an animation of two balls (planets) on a sheet.

All in all a nice page.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,621

Re: Gravity

hi MathsIsFun

Good page.  I found the animation tricky to use  but I think this has great potential.  Mostly, new particles either zoomed off or just crashed into the growing central mass.  After some practice I managed to get one particle to orbit the central mass.  The 'ellipse' had an axis progression (Mercury type orbit?).  Have you built in some Einsteinian relativity element or is this just an accuracy issue?  Would it be possible to provide greater control of each particle so it's easier to set up orbits?  eg create a new particle, then specify its direction of motion, then the magnitude of this motion.  That would allow controllable experimentation.

I made the central mass about 10 x 10^25 and the satellite 1 x 10^23.  I say 'about' because most of my attempted satellites just crashed into the 'planet'.  It took a while before I managed to get this one with the right tangential velocity.

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,713

Re: Gravity

I was thinking of a popup edit screen, one line per object, with mass, x and y position and velocity magnitude and direction (0-360 degrees). The animation would pause while editing. Can also delete a particle.

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"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,713

Re: Gravity

Updated Gravity Freeplay with an edit option, how is it?

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"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Gravity

Hi;

Could be a firefox issue but I can not produce an image like Bob did.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,621

Re: Gravity

Oh that's great!!!  

I chose 2 x 10^23 and 6 x 10^17 for a Sun and Earth system (scaled down mass-wise) and managed this straight away.  Think I need to adjust the velocity so that we don't all burn up on closest approach!

Nice demonstration of Kepler's laws too.

Oh joy.  I've just added Mars.  Shows opposition and all that.  This is better than 'sliced bread' !

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob