Question

A body of mass \( m \) rises to a height \( h = \frac{R}{5} \) from the earth's surface, where \( R \) is the earth’s radius. If \( g \) is acceleration due to gravity at the earth’s surface, then the increase in potential energy is:

• A. \( mgh \)
• B. \( \frac{4}{5} mgh \)
• C. \( \frac{5}{6} mgh \)
• D. \( \frac{6}{7} mgh \)

Hint:

For large heights comparable to Earth's radius, always use \[ \Delta U = GMm\left(\frac{1}{r_1} - \frac{1}{r_2}\right) \] instead of \( mgh \), which is only valid for small heights.

Answer 1

The Correct Option is C