# List of physics formulas class 11 chapter-Gravitation

## Basic forces in nature

• Gravitational force
• Electromagnetic force
• Strong nuclear force
• Weak nuclear force

The ratio strengths of gravitational, weak nuclear, electromagnetic and strong nuclear forces respectively are 1: 1031 : 1036: 1038

### Gravitation

Is the name given to the force of attraction between any two bodies of the universe.

### Gravity

Is the force of attraction exerted by earth towards its center on a body lying on or near the surface of earth. Gravity is merely a special case of gravitation and is also called earth’s gravitational pull. Weight of a body is defined as the force of attraction exerted by the earth on the body towards in centre.

Statement: The gravitational force of attraction between two bodies is directly proportional to the product of their (inertial) masses and inversely proportional to the square of the distance between their centres. This force acts along the line joining the centers of the two bodies.

### Definition of G

The universal gravitational constant is numerically equal to the force of attraction between two unit masses separated by unit distance.

### Value and units of G:

In S.I. 6.67× 10-11 newton – m2 kg-2

### Relation Between ‘G’ and ‘g’:

Relation between ‘Gravitational constant’ and acceleration dur to gravity is g = GM/R2

### Variation of ‘g’

• Acceleration dur to gravity at certain altitude (height) ‘a’ is given by

For h<<R

• Acceleration due to gravity at certain depth ‘d’ is given by

• Acceleration due to gravity at certain

Lattitude φ is given by

gφ = g-Rω2cos2φ

### Gravitational field strength

Gravitational field strength:It is defined as gravitational force per unit mass placed at that point.

E = F/M

On the surface of the earth

E = F/M = mg/m = g

### Chandrashekar limit

The maximum mass that a white dwarf can have is called the Chandrashekar limit. It is equal to 1.4 times the sun's mass.

### Frame of references

• A frame of reference describes the position of an object in space.
• There are two types of reference frames.
1. Inertial frame of reference: The frame of reference in which newton’s laws hold good is called the inertial frame of reference. Ex : The reference frame at rest.
2. Non-inertial frame of reference: The frame of reference in which newton’s laws of motion do not hold good is called the non-inertial frame of reference. Ex: The linearly accelerating frame (or) a rotating frame.
• The acceleration of due to real forces.
• The acceleration of a body in the non-inertial frame of reference is due to pseudo forces.

### Mass

Mass is defined as the amount of matter contained in a body. mass of a body can be found by two different methods. Those are

• Inertial mass: The property of a body to measure its resistance to acceleration is called its inertial mass.

• Gravitational mass: The property of a body responsible for the gravitational force it exerts on another body is called gravitational mass.

### Also Check

Do follow NCERT Solutions for class 11 physics prepared by Physicswallah. If any students need to take the online test to check their concepts or understanding then they can visit the online test for class 11.

Download the Pdf of class 11 physics formula sheet of chapter Gravitation from the link given below