The following Topics and Sub-Topics are covered in this chapter and are available on MSVgo:

The force of attraction between any two bodies is gravitation or simply gravity. For a certain degree of force, all objects in the universe attract each other. But in most situations, because of the very great distance of separation, the force is too small to be detected. Besides that, the spectrum of gravity is limitless. However, as objects move farther, the effect gets poorer.

With a force known as Gravitational Force, each body in this universe pulls other bodies to itself, so gravity is a study of the interaction between two masses. Of the two weights, the heavier one is considered the mass of the source, and the lighter one is called the mass of the test.

Gravitational force is a fundamental force that depends only on the source mass on the location of test mass and often operates along the line that joins the centers of the two masses.

The force exercised between two objects by each other is given by the following relationship, according to Newton’s Universal Law of Gravitation.

Fg∝(m1.m2)/r2

Where,

g: the force of gravitation between two bodies

m1: the mass of one object

m2: the mass of the second object

r: the distance between two objects’ centers

**Centripetal Force **

When a body undergoes circular motion, a force acting in the center of the circle is perceived. A centripetal force is what this center-seeking force is called.

**Free Fall and Motion**

Acceleration due to gravity is stable, when an object is under free fall,

g = 9.8ms^-2

The value of g does not depend on mass, i.e. any large or small particle feels the same acceleration due to free-fall gravity. For freely falling objects, all three equations of motion are true as they are under uniform motion.

The convention symbol: towards Earth g is +ve / away from Earth g is -ve.

**Mass and Weight **

An object’s mass is the measure of its inertia and is constant throughout the universe. If the value of g increases, an object’s weight keeps changing. Weight on an object = mg is nothing but an enticing power of the Planet.

The weight of an object on the Moon is 1/6 times that of the Earth’s weight.

**Thrust And Pressure **

It is called thrust, the force acting on an object perpendicular to the surface. The thrust effect depends on the region of interaction. The strain, per unit area, is thrust. The Pascal unit of the SI is (Pa). More friction is applied on a force acting on a smaller area than the same force acting on a wider area.

**Fluid pressure **

The strain exerted by the fluid in a jar is transferred to the walls of the container without decreasing in both directions.

The upward force exerted on an object by a fluid is known as upthrust or buoyant pressure.

The degree of buoyancy depends upon the fluid mass. If an object’s mass is smaller than the fluid, it can float. If the object’s mass exceeds that of the fluid, it will sink.

According to the theory of Archimedes, when a body is completely or partly immersed in a fluid, it feels an upward force proportional to the weight of the fluid that is replaced by it.

**Relative Density **

Relative density = A substance’s density / Water density

**The Falling Moon – Revolution of the Moon across the Earth **

Due to the centripetal force, which is the Planet’s force of gravity, the moon orbits around Earth. When the attraction force between the Planet and the moon disappears, the moon will begin to travel in a tangential straight-line direction to its orbit around the Earth.

**The Story of Gravity – Introduction to Gravity: Kepler’s Laws**

An ellipse with the sun as its focal point is the orbit of a planet. At similar periods of time, the line that joins the planets and the sun sweeps equal regions.

Square of the angular time period T ∝ Cube of the mean size of a planet from the sun.

r ^ 3 . α . T. ^ 2

This chapter taught us about the basics of gravitation. We learned about the concepts of gravity and its applications in the real world.

**1. What do you mean by gravitation? **

In mechanics, gravity, also known as gravitation, is the fundamental force of attraction working between all matter.

**2. What is the difference between gravity and gravitation? **

Although both concepts sound the same, momentum and gravity differ, gravity is the force that exists between two bodies, while gravity is the force that occurs between the earth and a body.

**3. What is the gravitation formula? **

The gravitational force mathematical formula is F=GMmr^2, where the gravitational constant is G.

**4. What are the 3 laws of gravity? **

Three Principles of Motion by Newton

- Until an external force acts on it, any entity in a state of uniform motion will stay in that state of motion.
- Force equals accelerating mass times.
- There is an equal and opposite answer to any action.

**5. How did Einstein explain gravity?**

Einstein argued that gravity is not at all a factor. He defined it as a curvature induced by mass and energy in time and space.

MSVgo is your one-stop solution for learning Gravitation through simple, interactive, and explanatory visualizations.