The kinetic energy needed to project a body of mass $m$ from the earth's surface (radius $R$ ) to infinity is
The kinetic energy needed to project a body of mass $m$ from the earth's surface (radius $R$ ) to infinity is
- A
$\frac {mgR}{2}$
- B
$2mgR$
- C
$mgR$
- D
$\frac {mgR}{4}$
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