Answer:

Explanation:
Consider two particles are initially at rest.
Therefore,
the kinetic energy of the particles is zero.
That initial K.E. = 0
The relative velocity with which both the particles are approaching each other is Δv and their reduced masses are

now, since both the masses have mass m
therefore,

= m/2
The final K.E. of the particles is

Distance between two particles is d and the gravitational potential energy between them is given by

By law of conservation of energy we have

Now plugging the values we get



This the required relation between G,m and d
Step 1: Look in your book or online for the conical pendulum equation.
Step 2: Look at the drawing and see which angle is involved in the equation.
Answer: It's Angle #2 in your drawing.
It's a measure of the acceleration