Gravity, Orbits, Projectile Motion

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Gravity, Orbits, Projectile Motion

• Physical Science 9

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Gravity

• The attraction or pulling force between all matter

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Gravity

• Is what holds everything on Earth on the ground
  and stops it from flying off into space. It
  holds the Earth together, keeps the moon orbiting
  Earth, and the Earth and all the planets orbiting
  the Sun.

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Gravity

• The force of gravity depends on mass and distance
• The more mass an object has, and the closer it is
  to another object, the more strongly its gravity
  pulls

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Orbit

• The result of a perfect balance between the force
  of gravity on an object (which pulls it inward
  toward whatever is orbiting) and its forward
  momentum (which keeps it flying straight)

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Orbit

• Orbit means travel around and a moon, planet,
  or other space object may be held within a larger
  space objects gravitational field and orbit it.

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Orbit

• Orbits can be circular, elliptical, or parabolic

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Satellite

• An orbiting space object

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Momentum

• What keeps a satellite moving through space.
  Just how much momentum a satellite has depends on
  its mass and its speed.

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Momentum

• A satellite orbits at the height where its
  momentum exactly balances the pull of the larger
  objects gravity.

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Satellite

• If the gravitational pull is greater than a
  satellites momentum, it falls toward the larger
  space object.

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Satellite

• If a satellites momentum is greater than the
  pull of the larger objects gravity, it flies off
  into space.

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Satellite

• The lower a satellite orbits, the faster it must
  travel to stop it falling in toward the larger
  space object.

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Projectile

• Anything that is thrown or shot through the air
  is called a projectile.
• Because of the Earths gravitational pull and
  their own inertia, projectiles follow a curved
  path.

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Newtons 1st Law

• Object in motion will stay in motion
• A center seeking force is required to cause an
  object to move in a circle.

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Centripetal

• Center Seeking
• In the case of the Earths Circular motion around
  the Sun, the centripetal force causing that
  motion is the result of the gravitational
  attraction between them.