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Grade 6Mechanics

Energy required to move a body of mass m from an orbit of radius 2R to 3R is
(a) GMm/12R2
(b) GMm/3R2
(c) GMm/8R
(d) GMm/6R

Profile image of Lokesh kumar
12 Years agoGrade 6
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3 Answers

Profile image of Deepak Patra
12 Years ago

(d) Energy required = (Potential energy of the Earth – mass system when mass is at distance 3R) – (Potential energy of the Earth-mass system when mass is at distance 2R)

= - GM/3R – (-GM/2R) = - GM/3R + GM/2R

= -2GMm+3GMm / 6R = GMm/6R
Profile image of Mallikarjun
8 Years ago
Potential energy U=-GMm/rTo get energy required to move a body of mass m from 2R to 3R we have to subtract the energy required to move the body from earth to 2R, from the energy required to move the body from earth to 3RHence U=-GMm/3R -(-GMm/2R) =GMm6R
Profile image of Yash Chourasiya
6 Years ago
Dear Student

Energyrequired = (Finalpotential – Initialpotential)m
Energyrequired = (−GMm/​3R)− (−GMm/2R)
​Energy Required = GMm/6R​

I hope this answer will help you.
Thanks & Regards
Yash Chourasiya