WEEK 3

• Philosophiæ Naturalis Principia Mathematica


  • written by Isaac Newton
  • Where he introduced the law of universal gravitation
  • This work helped bridged the gap between earthly and celestial mechanics, unifying the physics of both realms
• Law of universal gravitation


  • states that every particle attracts every other particle in the universe, with a force, directly proportional to the product of the masses,
  • inversely proportional to the square of the distance between them
• Importance of the law of universal gravitation

  • explains why objects fall to the ground
  • Help in understanding planetary motion, and celestial mechanics
  • Forms the basis for orbital mechanics and space exploration
  • Supports the motion of tides due to the gravitational pull of the moon and sun
  • provides a foundation for engineering structures like skyscrapers, ensuring that they withstand gravitational forces
  • Please a crucial role in understanding p differences on different planets
• The moon’s gravitational influence on tides

  1. the moon exerts, a gravitational pull on earth, attracting ocean water
  2. This creates a bulge of water (high tide) on the side of the Earth, facing the moon
  3. Simultaneously, another high tide occurs on the opposite side of the earth, because of the earth being pulled slightly more than the water on its far side, creating a secondary bulge
  4. Areas between these bulges experience low tides
• Mass


  How much matter is inside an object
• Weight


  How strong gravity pulls on that object
• Spring tides


  • stronger tides
  • Occurs when the sun, moon and earth are aligned during a full moon and new moon
  • The gravitational forces of the moon and sun combine, resulting in higher high tides, and lower low tides
• Neap tides


  • weak tides
  • This occurs when the sun and moon form a right angle with earth (during first quarter and third quarter moons)
  • The gravitational forces, partly cancel each other out, leading to lower high tides and higher low tides