Question

If a body of mass \(m\) has to be taken from the surface of earth to a height \(h = R\), then the amount of energy required is (\(R\): radius of earth)

• A. \(mgR\)
• B. \(\frac{mgR}{3}\)
• C. \(\frac{mgR}{2}\)
• D. \(\frac{mgR}{12}\)
• E. \(\frac{mgR}{9}\)

Hint:

For heights comparable to the Earth's radius, do not use \(mgh\). Instead, use the general formula: \(\Delta U = \frac{mgh}{1 + \frac{h}{R}}\). Substituting \(h = R\) gives \(\Delta U = \frac{mgR}{1 + 1} = \frac{mgR}{2}\).

Answer 1

The Correct Option is C