piyopiyo 發表於 22-9-2008 06:01:21

原帖由 x-Stephen-x 於 21-9-2008 23:39 發表 http://www.nakuz.com/bbs/images/common/back.gif
with air resistance,that means the satellite will decelerate(linearly) , so the satellite will go a lower potential level,which increase its linearly speed.
as T^2 = 4pi^2 r^3/ GM , r decrease=>t dec ...
I got ur meaning
how about B,angular momentum?-.-...is it mw??
if mw decreases...with m being constant...then w should decrease-,-...[]??

j32738 發表於 22-9-2008 18:13:02

Are u using New way?
This one need to use Keplers LAW

you studied very fast...

piyopiyo 發表於 22-9-2008 18:38:29

原帖由 j32738 於 22-9-2008 18:13 發表 http://www.nakuz.com/bbs/images/common/back.gif
Are u using New way?
This one need to use Keplers LAW

you studied very fast...
yes
however,i have a problem
according to wiki
angular momentum = rxp
where p is the linear momentum of the object and r is the radius
and x is the vector cross product[]

好複雜[]
但其實 r同p都係成90度, angular momentum即係都係 rp[]
r下跌,但p=mv,,v上升...
咁我都唔知r跌得勁定v升得勁
定係又要另外再prove[]

Zend 發表於 22-9-2008 19:35:00

transform to one variable lor
and one more thing

r decreases, v increases, but v increasesand v = sqrt GM/r(it still follows a circular orbit, so the KE is due to circulation, and circulation=> centripetal force necessary for uniform circular motion


ne 個時候我應該仲係chapter 2

不過講樣事實比你聽, gravitation 好多年都無再出LQ
只得MC

x-Stephen-x 發表於 22-9-2008 20:13:55

as mv^2/r = GMm/r^2 => v=(GM/r)^1/2 ,
angular momentum =mvr = m(GM)r^1/2 , as r decrease , angular momentum decrease

adamsteve 發表於 23-9-2008 22:02:46

其實換個方法諗就係話
如果時間真係increase左 姐係佢速度慢左
速度慢左 根本就唔應該 或者應該話佢根本無能力再留係哥條orbit上面

咁佢都講得佢一定係哥條orbit度所以速度一定唔會改變 所以時間都唔會變

x-Stephen-x 發表於 23-9-2008 23:09:30

回復 10# 的帖子

i mean 舊野係transverse deceleration but not radial...

j32738 發表於 24-9-2008 13:37:08

原帖由 piyopiyo 於 22-9-2008 18:38 發表 http://www.nakuz.com/bbs/images/common/back.gif

yes
however,i have a problem
according to wiki
angular momentum = rxp
where p is the linear momentum of the object and r is the radius
and x is the vector cross product[]

好複雜[
I have never seen angular momentum
I think it is OUT C

also for moment of inertia
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