Question

A body of mass m is taken from earth surface to the height h equal to radius of earth, the increase in potential energy will be

• A. $m g R$
• B. $\frac { 1 } { 2 } m g R$
• C. $2 m g R$
• D. $\frac { 1 } { 4 } m g R$

Answer 1

Answer: (B)

$\frac { 1 } { 2 } m g R$

Answer 2

Work done $= \frac { m g R } { 1 + R / R }$ $= \frac { 1 } { 2 } m g R$ .