Two bodies of masses `m_(1)" and "m_(2)` are initially at rest at infinite distance aprat. They are then allowed to move towards each other under mutual gravitational attraction. Their relative velocity of approach at a separation distance r between them is

Options

A. `[2G ((m_(1)-m_(2)))/(r )]^(1/2)`
B. `[(2G)/(r ) (m_(1)+m_(2))]^(1/2)`
C. `[(r )/(2G (m_(1)m_(2)))]^(1/2)`
D. `[(2G)/( r) m_(1)m_(2)]^(1/2)`

Answer

B