Home » Ask & Discuss » Physics. » Mechanics « Back to Discussion

Mechanics

Scorching goIITian

Joined:	11 Jun 2007
Post:	239

16 Sep 2007 21:54:40 IST

0 People liked this

434

rotational dimensions

None

1)if the ice at poles melt & flow towards equator,how will the duration of day night
be affected

2)when tall buildings are constructed on eartg, the duration of day night slightly increases.is the statement true or false

explain with the help of conservation of angular momentum

Share this article on:

Comments (2)

Purav Master

Blazing goIITian

Joined: 9 Nov 2006

Posts: 814

17 Sep 2007 09:44:09 IST

Like 2 people liked this

When ice at the poles melt, it would flow in the oceans and so the bulk of water in the ocean increases.

Now the earth will have a higher moment of inertia as the mass distribution is more at the equatorial region due to rise in water level. So the angular speed will decrease to conserve angular momentum. Thus days and nights will become longer.

When we contruct tall buildings, they tend to increase moment of inertia. (Now we have more mass rotating. As the buildings go taller, they will affect more because the mass distribution is away from axis of rotation) However a few ones won't create much difference as they have no dimensions (and mass) compared to the earth. However a large number of buildings can increase the moment of inertia significantly and make days longer.

So the given statement is true.......

raymont cherian

Cool goIITian

Joined: 3 Jul 2007

Posts: 46

22 Sep 2007 23:02:05 IST

Like 0 people liked this

firstlywen v consider earth's rotation v take earth 2 b a sphere..so mass wudnt matter were it was...(on the surface) as the radius wud be the same.. then if v want the real earth a lot will matter..
bcuz there is redistribution of mas in the ocean constantly nd stuff like dat.. tides etc....v also hav to see were the distance from COM is more.. at equator or poles.. them greater the mass at farther distance will increase MOI nd ang momntm wl dec..

as far as the buildings are concerned .. it cant increase the mass of the earth as it was made off the earth using iron and cement on earth.. yes it increases moment of inertia so (dmr^2) so by cons of ang. momntm. .. it shud dec the ang vel. thereby inc duration...

Quick Reply

Reply

	Some HTML allowed.
	Keep your comments above the belt or risk having them deleted.
	Signup for a avatar to have your pictures show up by your comment
	If Members see a thread that violates the Posting Rules, bring it to the attention of the Moderator Team