Question

Question :- Give a brief Explanation on Gravitational Force. (Class 9 Physics)

● Answer Should Be Long.

● Spams Will Be Reported.

● Correct Answer Would Be Selected As Brainliest.


I HOPE FOR A GREAT ANSWER!!​

Answer 1

Answer:

$\bigstar\:\underline{\boxed{\bf{\red{Gravitational\:Force :}}}}$

➳ The force which attracts any two objects is called Gravitational force.

➳ It is an attractive force.

✴ Name : Gravitational force

✴ Relative strength : 10$^{-39}$

✴ Range : Infinite

✴ Operates among : All objects in the universe.

➳ The magnitude of gravitational force between two point masses is directly proportional to the product of masses and inversely proportional to the square of the distance between them. This is known as Newton's universal law of Gravitation also known as inverse square law.

➳ Let two objects of masses M and m are placed at distance r. Gravitational force acts between them is given by

$\dag\:\underline{\boxed{\bf{\purple{F=\dfrac{GMm}{r^2}}}}}$

Where,

• G denotes gravitational constant
• M & m denotes masses
• r denotes distance

⇒ The law of gravitation is strictly true for point masses.

However, it is valid in the following circumstances also :

• For two bodies at any size provided they both have spherical symmetry.
• When one body has spherical symmetry and the other is small compared with the separation between their centres.
• When neigher body has spherical symmetry but both arr small comparrd with the separation between their centres.

⇒ The value of G does not depend on the nature and size of the masses.

⇒ The law of gravitation is universally valid. It applies to small objects on the earth, planets in the solar system and to galaxies.

⇒ Though the gravitational force between two particles is central, the force b/w two finite rigid bodies is not necessarily along the line joining their centre of mass. For a particle lying outside a spherical, symmetric body, the force acts as if the mass is concentrated at the centre of the body. Therefore, this force is central.

✴ Fundamental forces in nature :

1. Gravitational force
2. Weak nuclear force
3. Electromagnetic force
4. Strong nuclear force