law of universal gravitation

• Gravity

  • is one of the fundamental forces - the force which acts on all objects at or near the surface of the earth
  • Newton’s thinking was that the force exerted by the earth on any falling body near the earth’s surface is of the same nature as the force exerted by the sun on any planet.
• Gravitation - Is the force of attraction between any two bodies in the

  universe
• The distance between their centers is radius.
• Every particle in the universe

  attracts every other particle

  with a force which is directly

  proportional to the product of

  their masses and inversely

  proportional to the square of

  the radius between their

  centers.
• Newton was able to show that heavenly bodies

  obey the universal law. From this fact, he

  concluded that the celestial bodies in solar

  system move in orbits. Such motion is

  determined by mutual attraction. Based on this

  concept, Newton considered the mutual

  attraction among the sun, earth, and the moon.
• weight of the body is

  the pull of gravity on

  that body. It is also

  the vector sum of all

  the gravitational

  forces acting on the

  object.
• weight and gravity are directly proportional to each other.