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Mechanics

Scorching goIITian

 Joined: 5 Apr 2008 Post: 269
21 Nov 2008 21:15:17 IST
0 People liked this
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Gravity
Engineering Entrance , Medical Entrance , AIPMT , JEE Main , AIIMS , JEE Advanced , Physics , Mechanics

Hello,

I read in a book that the formula   is not applicable to calculate 'g' inside the earth's surface.

Is it true.

If yes then why.

Hot goIITian

Joined: 19 Nov 2008
Posts: 134
21 Nov 2008 21:21:37 IST
1 people liked this

ya it is true...

as we go below d earth surface... d effective mass of earth dat exerts gravitational force will decrease and also d radius will decrease... hence v cannot use d formula g = GM / R^2 ...

rather d formula would be... g' = (GM / R^2).(1-h/R) = g(1-h/R)...

hope u got it...

rate if found useful...

Scorching goIITian

Joined: 29 Oct 2008
Posts: 298
21 Nov 2008 21:22:45 IST
1 people liked this

Because inside the earth, the gravitational force is not exrted by whole mass of earth.

Suppose, an object is at depth 'd' from surface of earth, then only the sphrical mass having radius (R-d) will exert gravitational force on the object.

At depth d, the formula changes as,

Scorching goIITian

Joined: 5 Apr 2008
Posts: 269
10 May 2009 19:54:28 IST
0 people liked this

thanx

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