🌍 Gravitation
Introduction
Gravitation is the force of attraction between any two objects in the universe. It was first
explained by Sir Isaac Newton, who stated that every object attracts every other object with
a force that is directly proportional to the product of their masses and inversely proportional
to the square of the distance between them.
Newton’s Law of Gravitation
The law is expressed as:
[ F = G \cdot \frac{m_1 \cdot m_2}{r^2} ]
Where:
(F) = gravitational force
(m_1, m_2) = masses of the two objects
(r) = distance between their centers
(G) = universal gravitational constant ((6.67 \times 10^{-11} , N \cdot m^2/kg^2))
Gravity on Earth
Earth attracts all objects towards its center.
The acceleration produced due to gravity is denoted by (g).
Value of (g) on Earth ≈ 9.8 m/s².
(g) is nearly constant near Earth’s surface but decreases slightly with altitude.
Free Fall
When an object falls under the influence of gravity alone, it is said to be in free fall.
Equations of motion apply with acceleration (a = g).
Examples: falling stone, raindrops.
Mass and Weight
Mass: Amount of matter in a body; constant everywhere.
Weight: Force with which Earth attracts a body; given by (W = m \cdot g).
Weight changes with location (less on Moon, more on Earth), but mass remains the
same.
Motion of Planets and Satellites
Introduction
Gravitation is the force of attraction between any two objects in the universe. It was first
explained by Sir Isaac Newton, who stated that every object attracts every other object with
a force that is directly proportional to the product of their masses and inversely proportional
to the square of the distance between them.
Newton’s Law of Gravitation
The law is expressed as:
[ F = G \cdot \frac{m_1 \cdot m_2}{r^2} ]
Where:
(F) = gravitational force
(m_1, m_2) = masses of the two objects
(r) = distance between their centers
(G) = universal gravitational constant ((6.67 \times 10^{-11} , N \cdot m^2/kg^2))
Gravity on Earth
Earth attracts all objects towards its center.
The acceleration produced due to gravity is denoted by (g).
Value of (g) on Earth ≈ 9.8 m/s².
(g) is nearly constant near Earth’s surface but decreases slightly with altitude.
Free Fall
When an object falls under the influence of gravity alone, it is said to be in free fall.
Equations of motion apply with acceleration (a = g).
Examples: falling stone, raindrops.
Mass and Weight
Mass: Amount of matter in a body; constant everywhere.
Weight: Force with which Earth attracts a body; given by (W = m \cdot g).
Weight changes with location (less on Moon, more on Earth), but mass remains the
same.
Motion of Planets and Satellites
