According to Newton's law of gravitation,every object in the universe exerts a gravitational force on every other object. Why do two objects not move towards each other?

Two metallic spheres each of mass $M$ are suspended by two strings each of length $L$. The distance between the upper ends of the strings is $L$. The angle which the strings will make with the vertical due to the mutual attraction of the spheres is

Find the acceleration of our galaxy due to the nearest comparably sized galaxy. The approximate mass of each galaxy is $8 \times 10^{11}$ solar masses,and they are separated by $2 \times 10^6$ light-years. Each galaxy has a diameter of $10^5$ light-years. (Assume $1 \text{ light-year} \approx 10^{16} \text{ m}$,gravitational constant $G \approx 10^{-10} \text{ Nm}^2/\text{kg}^2$,and mass of the Sun $= 2.0 \times 10^{30} \text{ kg}$)

The gravitational force $F_g$ between two objects does not depend on

Mass $M$ is divided into two parts $xM$ and $(1-x)M$. For a given separation,the value of $x$ for which the gravitational attraction between the two pieces becomes maximum is

There are three arrangements of three point masses (each of mass $m$). In which of the following three arrangements are they arranged in order of increasing magnitude of the net gravitational force on the point mass marked as $1$?