InterviewSolution
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n1. Ifg is the acceleration due to gravity on thesurface of the earth, the gain in potentialenergy of an object of mass in raised fromthe earth's surface to a height equal to theradius Ro the earth is |
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Answer» Let R→Radius of the earth M→Mass of the earth m→Mass of the body g→Acceleration due to gravity on earthWhen the body is on earth surface, considering the force of attraction of earth on it we can write mg = GMm/R^2 where G = Gravitational constant ⇒GM = gR^2.....(1) Now the PE of the system when the body is on the surface Es = −GmMR....(2) Again the PE of the system when the body is at height h from the the earth surface is given by Eh = −GmM/R+h If h = R then ER = −GmM/R+R = −GmM/2R....(3) Soincrease in PEdue to shift of the body of massmfrom surface to the height equal to the radius (R) of the earth is given by: ΔEp = ER−Es = −GmM/2R + GmM/R = GmM/2R = mgR^2/2R = 1/2mgR Inserting GM = gR^2 from (1) |
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