Gravitation

Two uniform solid spheres

of equal radii R, but mass M and 4 M have

a centre to centre separation 6 R, as shown

in Fig. 7.10. The two spheres are held fixed.

A projectile of mass m is projected from the

surface of the sphere of mass M directly

towards the centre of the second sphere.

Obtain an expression for the minimum

speed v of the projectile so that it reaches

the surface of the second sphere.