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A body of mass m is placed on earth surface which is taken from earth surface to a height of h=3 R, then change in gravitational potential energy is |
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Answer» `(mgR)/(4)` Gravitational potential energy at a height h=3R `=-(GM m)/(R+h)=-(GM m)/(R+3R)=-(GM m)/($r)` `:.` Change in potential energy `=-(GM m)/(4R)-(-(GM m)/(R ))=-(GM m)/(4R )+(GM m)/(R )=(3)/(4)(GMm)/(r )` Again, we have, `(GM m)/(R^(2))=MG` (where g is acceleration due to GRAVITY on earth.s surface). `:. (GM m)/(R^(2))=mgR`. `:.` Change in potential energy `=(3)/(4)mgR`. |
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