GRAVITATION

 Gravitation is a force of attraction that acts between any two objects in the universe. It is one of the four fundamental forces of nature

Newton’s Law of Universal Gravitation

•Every object attracts every other object with a force:

•F = G * (m1 * m2) / r^2

 

•Where:

•F = Force

•G = 6.674×10⁻¹¹ Nm²/kg²

•m1, m2 = masses

•r = distance between them

Free Fall

Objects falling under gravity alone are in free fall.

•Acceleration due to gravity: g = GM / R²

•On Earth, g ≈ 9.8 m/s²

Mass vs Weight

Mass: Amount of matter, remains constant

•Weight: Force due to gravity

•W = mg

Kepler’s Laws of Planetary Motion

1. Law of Orbits: Planets move in elliptical orbits.

•2. Law of Areas: Equal areas in equal times.

•3. Law of Periods: T² ∝ R³

Satellites

Artificial Satellite: Man-made object in orbit.

•Orbital Velocity: v = √(GM/R)

•Escape Velocity: ve = √(2GM/R) ≈ 11.2 km/s on Earth

Applications of Gravitation

• Satellite Communication

•• Planetary Motion Prediction

•• Ocean Tides

•• Rocket Launching.