Grade 11Mechanics

The gravitational potential energy of a body at a distance r from the centre of earth is U. Its weight at a distance 2r from the centre of earth is

a) U/r

b) U/2r

c) U/4r

d) U/root[2]r

Arnab Mandal

14 Years agoGrade 11

2 Answers

Ashwin Muralidharan IIT Madras

Approved Tutor Answer14 Years ago

Hi Arnab,

The Gvt Potential Energy at a distance R is,

U = GMm/r

And weight at distance 2r is

W = GMm/(2r)² = GMm/4r² = U/4r.

Hence Option (C).

Hope this helps.

Best Regards,

Ashwin (IIT Madras).

nikhil manali

14 Years ago

no since u=GMm/r

and GM/r2=g r2 is r square

so GM=gr2

therefore u=gr2m/r

and mg= w

u=wr since r2 and r wiil be divedid by each other

now r=2r

so w=u/2r

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The gravitational potential energy of a body at a distance r from the centre of earth is U. Its weight at a distance 2r from the centre of earth is a) U/r b) U/2r c) U/4r d) U/root[2]r

Arnab Mandal

2 Answers

Ashwin Muralidharan IIT Madras

nikhil manali

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