why is the value of 'g' 0 at the centre? why is the force of attraction between two object is measured using centre to centre distance?

Asked by Sushant Kumar | 12th Oct, 2013, 02:59: PM

Expert Answer:

The formular for g = GM/R2 is valid outside the earth, that is from surface of earth to outwards.
 
But, inside earth, mass is not uniform. Hence, we need to consider the variation in terms of density.
 
 
Thus, inside earth, g is directly proportional to radius and density.
Now, at centre R = 0.
 
Thus, g = 0 at centre.
 
The force of attraction between two objects is measured along centre to centre distance because, we consider that entire mass of the body is supposed to be concentrated at its centre, called the centre of mass. Thus, we consider that whole mass is concentrated at the point which is the centre of the body.

Answered by Romal Bhansali | 12th Oct, 2013, 05:36: PM

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