# Given a thin homogeneous disc of radius R and mass m1. A particle of mass m2 is placed at a distance L from the disc on its axis of symmetry. Initially. Both are motionless in free space but they ultimately collide because of gravitational attraction between them. The relative velocity at the time of collision is (L >> R)

Q: Given a thin homogeneous disc of radius R and mass m1. A particle of mass m2 is placed at a distance L from the disc on its axis of symmetry. Initially. Both are motionless in free space but they ultimately collide because of gravitational attraction between them. The relative velocity at the time of collision is (L >> R)

(a) $\sqrt{2G (m_1 + m_2 )(\frac{2}{R} – \frac{1}{L})}$

(b) $\sqrt{2G (m_1 + m_2 )(\frac{2}{R} + \frac{1}{L})}$

(c) $\sqrt{2G (m_1 + m_2 )(\frac{1}{R} + \frac{2}{L})}$

(d) $\sqrt{2G (m_1 + m_2 )(\frac{1}{R} – \frac{2}{L})}$