A body released at the distance `r(r gt R)` from the centre of the earth. What is the velocity of the body when it strikes the surface of the earth?

Explanation

To find the velocity of a body when it strikes the surface of the Earth after being released from a distance \( r \) (where \( r > R \), with \( R \) being the radius of the Earth), we can use the principle of conservation of energy. Here’s a step-by-step solution:

### Step 1: Understand the Energy Conservation Principle
The total mechanical energy (potential energy + kinetic energy) of the body remains constant if we ignore air resistance. Initially, the body has gravitational potential energy and no kinetic energy since it is released from rest.

### Step 2: Calculate Initial Potential Energy
The gravitational potential energy \( U \) at a distance \( r \) from the center of the Earth is given by:
\[
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