BRAINCAKE

Gravitational Fields

OCR A-level PhysicsTopic 3 of 1114 lessons

Revision notes for Gravitational Fields in OCR Physics A (H556). Read the start of any lesson here, then sign in free for the whole lesson, the R.E.C.I.P.E. recall steps and the quiz.

  1. Gravitational Fields.The mass of an object creates a force field around itself.
  2. The Strength of a Gravitational Field.The path which a small 'test' mass placed in a gravitational field is called a field line.
  3. Free fall in a gravitational field.An object with mass m in a gravitational field will experience a gravitational force F = mg which is equal to its weight Provided that no other…
  4. The Earth's gravitational fieldThere are different types of field: electric, magnetic and gravitational.
  5. Gravitational Potential.In order to escape a planet's gravitational pull, a rocket's engine must do work when it rises from the surface of a planet.
  6. Gravitational Potential.An object has gravitational potential energy due to its position in the earth's gravitational field.
  7. Equipotentials.Equipotentials are lines that join points with the same gravitational potential.
  8. The potential gradient.The potential gradient at a point in a gravitational field is the change in gravitational potential per metre.
  9. Newton's Law of Gravitation.Kepler made measurements of the motion of each planet.
  10. Gravitational Field Strength - g.Newton's law of gravitation can be applied to the gravitational field strength g = F/m.
  11. Gravitational Potential.Starting from the surface of a spherical planet, the gravitational potential at a point a distance - r - from the centre of mass of the planet is…
  12. Potential GradientsThe gradient of the tangent at any point on the gravitational potential curve is equal to the gravitational potential gradient
  13. Area Under a Force vs Distance GraphThe diagram shows the force needed to move a 1kg mass in a gravitational field (N) with the distance moved (m).
  14. SatellitesIn order for a satellite such as the moon to travel in a circular orbit around a planet there needs to be a centripetal force The centripetal force…

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