Question

The kinetic energy needed to project a body of mass $m$ from the earth surface to infinity is

• A. $\frac{1}{2}$mgR
• B. $2mgR$
• C. $mgR$
• D. $\frac{1}{4}$mgR

Answer 1

Answer: (C)

$mgR$

Kinetic energy required $=\frac{1}{2}m{V}_e^2$$=\frac{1}{2}m(\sqrt{2gR}{)}^2=mgR$