Two bodies of masses `m_(1)` and `m_(2)` are initially at rest a infinite distance apart. They are then allowed to move towards each other under mutual gravitaitonal 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