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InterviewSolution
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If g is the acceleration due to gravity on the earth’s surface, the gain in the potential energy of an object of mass m raised from surface of the earth to a height equal to radius R of the earth is - [M = mass of earth]A. 2mgRB. mgRC. `1/2` mgRD. `1/4` mgR |
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Answer» Correct Answer - C The potential energy of an object at the surface of the earth `U_(1)=-(GMm)/(R )` The potential energy of the object at a height h =R from the surface of the earth `U_(2)=-(GMm)/(R+h)=-(GMm)/(R+R)` hence the gain in potential energy of the object `triangleU=-(GMm)/(2R)+(GMm)/(R )` `=1/2 . (GMm)/(R )` But we know that `GM=gR^(2)` hence `triangle U =1/2 (gR^(2)m)/(R )=1/2gRm=1/2mgR` |
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