Optics

Lakshya Bhardwaj's Avatar
Hot goIITian

Joined: 20 Jul 2008
Post: 137
1 Oct 2008 19:56:48 IST
0 People liked this
2
884 View Post
Duration of day when there is no atmosphere on Earth? How to calculate it?
Engineering Entrance , Medical Entrance , NEET , JEE Main , AIIMS , JEE Main & Advanced , Physics , Optics

It is said that if there will be no atmosphere on Earth then the duration of the day will decrease by 4 minutes. OK, I understood that it will decrease but how to get that value (4), how to get its solution by a mathematical method?



Comments (2)

Sagar Saxena's Avatar

Blazing goIITian

Joined: 8 Oct 2008
Posts: 8064
11 Oct 2008 00:05:51 IST
3 people liked this

hello dear,


This question can be solved by thinking in a very analytical way..


There can be two solution to this problem,the one iam giving is very accurate and the other is not logicaly correct which i can also prove as that solution have some logical flaw...


method 1


As the atmosphere rotates with the earth,if earth dont have atmosphere than moment of inertia decreases hence,omega (angular velocity) increases as angular momentum is constant....L = I W;when angular velocity incraeses than Time decrease as T = 2 * pi  / w;


method 2;


It can also be understand by the fact that the air friction ,decreases the angular velocity hence TIME increases (by obove relation) and vice versa


Note:


obove concept is wrong because atmosphere always moves with the earth,so thr is no friction between themm(air friction)...if thr is air friction than we all will burn due to it(but it doesnt hapens)


 


i dont think so thr is ne mathematical relation for it,as all these are calculated by taking an assumptions..


let me know ,if u need more clearification for this

Lakshya Bhardwaj's Avatar

Hot goIITian

Joined: 20 Jul 2008
Posts: 137
11 Oct 2008 10:51:44 IST
0 people liked this

Sir, I just wanted to know from where that value 4 came from. OK I know that time will decrease. That can also be understood by another method that as there will be no atmosphere the light will travel at its usual speed and hence time of the day will decrease. Moreover, the delayed sunset and advanced sunrise will not happen and so the duration of day will again decrease.

But, my main question is that - Is there any calculation from where this value 4 minutes came from?



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
Free Sign Up!
Sponsored Ads

Preparing for JEE?

Kickstart your preparation with new improved study material - Books & Online Test Series for JEE 2014/ 2015


@ INR 5,443/-

For Quick Info

Name

Mobile

E-mail

City

Class

Vertical Limit

Top Contributors
All Time This Month Last Week
1. Bipin Dubey
Altitude - 16545 m
Post - 7958
2. Himanshu
Altitude - 10925 m
Post - 3836
3. Hari Shankar
Altitude - 10085 m
Post - 2217
4. edison
Altitude - 10825 m
Post - 7804
5. Sagar Saxena
Altitude - 8635 m
Post - 8064
6. Yagyadutt Mishr..
Altitude - 6330 m
Post - 1958

Find Posts by Topics

Physics

Topics

Mathematics

Chemistry

Biology

Parents Corner

Board

Fun Zone