Two objects are placed at a certain distance from each other in air. If they are placed at the same distance in water,what is the ratio of the gravitational force between them?

Let $G, W, E$ and $S$ be the relative strengths of gravitational, weak-nuclear, electromagnetic, and strong-nuclear forces, respectively. Which of the following statements is correct?

Two spheres of masses $m$ and $M$ are situated in air and the gravitational force between them is $F$. The space around the masses is now filled with a liquid of specific gravity $3$. The gravitational force between the bodies will now be

Two masses $m_1$ and $m_2$ $(m_1 < m_2)$ are released from rest from a finite distance. They start moving under their mutual gravitational attraction.

How much force of gravitation acts on a body at an infinite distance from the Earth?

The gravitational force between two point masses $m_1$ and $m_2$ at a separation $r$ is given by $F = k \frac{m_1 m_2}{r^2}$. The constant $k$: