Two identical particles each of mass $m$ go round a circle of radius $a$ under the action of their mutual gravitational attraction. The angular speed of each particle will be

$A$ system consists of three particles each of mass $m_1$ placed at the corners of an equilateral triangle of side $\frac{L}{3}$. $A$ particle of mass $m_2$ is placed at the midpoint of any one side of the triangle. Due to the system of particles,the force acting on $m_2$ is

State Newton's universal law of gravitation and represent it in a mathematical expression.

Explain the principle of superposition for gravitational force.

Two point masses $m$ and $4m$ are separated by a distance $d$ on a line. $A$ third point mass $m_0$ is to be placed at a point on the line such that the net gravitational force on it is zero. The distance of that point from the $m$ mass is:

Three particles each of mass $m_{1}$ are placed at the corners of an equilateral triangle of side $\frac{L}{3}$. $A$ particle of mass $m_{2}$ is placed at the midpoint of any one side of the triangle. Due to the system of particles,the net gravitational force acting on $m_{2}$ is ($G$ = Universal constant of gravitation).