gravitational fields

• what is newtons law of gravitation

  the gravitational force between two point masses is proportional to the product of the masses and inversely proportional to the square of their separation
• what must you make sure you do in an exam with the distance from the surface of a plant and its radius

  add them together
• what is a gravitational field 


  A region of space where a test mass experiences a force due to the gravitational attraction of another mass
• what does a large mass mean for the gravitational force

  a greater force is felt
• what is gravitational field strength at a point 


  The force per unit mass experienced by a test mass at that point
• an objects mass remains the same at all points in space
• what factors effect the gravitational field strength at the surface of a planet

  the radius and the mass
• the gravitational field strength is inversely proportional to the square of the radial distance
• when is an object regarded as a point mass

  when it covers a very large distance compared to its size
• what are radial fields considered

  non-uniform fields so the gravitational field strength is different depending on how far an object is from the centre of mass
• what is gravitational potential at a point

  The work done per unit mass in bringing a test mass from infinity to a defined point
• what value is the gravitational potential always

  negative
• what does gravitational potential depend on

  the mass and distance from the centre of mass
• why is the gravitational potential always negative

  the potential when r is at infinity is defined as zero
• GPE = mg
• force is inversely proportional to the r squared
• what does the area under a force-distance graph equal to

  the energy transferred/ work done
• what is the gravitational potential at a point defined as 


  The gravitational field at a particular point is equal to the negative gradient of a potential-distance graph at that point
• what are equipotential lines

  lines that demonstrate that the gravitational potential in a gravitational field and are always drawn perpendicular to the field lines
• what are equipotential lines always

  perpendicular to the field lines in both radial and uniform, dotted lines
• what are equipotential lines like in a radial field

  concentric circles, further apart when further away from the planet
• what are equipotential lines like in a uniform field

  horizontal, parallel, equally spaced
• no work is done when moving along an equipotential line, only between equipotential lines