The object with mass m is placed halfway between an object of mass M and an object of mass 3M which are separated by a distance d. Find out the magnitude of force on the object with mass m?
i) 8GMm/d^2
ii) GMm/(4d^2)
iii) 4GMm/d^2
iv) GMm/(2d^2)
v) 3GMm/2d^2