# a level physics

 The flashcards below were created by user ghoran on FreezingBlue Flashcards. a gravitational field is a region where any other mass will experience a force the gravitational field strength , g , at a point us defined as the force that acts on a unit mass placed at that point g = F/m units Nkg-1vector quantity a gravitational field can be represented by sketching field lines around a mass the field lines show the direction of force that acts on another mass near the earths surface the field lines are approx parallel to each other and perpendicular to the surface of the earth , the field is said to be uniform - the gravitational field strength is the same magnitude and direction throughout the field on a larger scale the field lines around a spherical mass spread out radially force of gravity on a small mass near a much larger spherical mass is always directed to the centre of the larger mass the magnitude of g in a radial field .... with increased distance from the massive body decreases over small distances which are much less than the earths radius the change in gravitational field strength is insignificant so the field is considered to be uniform for a radial field such as that due to a spherical mass , M , the force that acts on a small mass , m , placed at distance , r, is given by Newtons law as F = GMm/r2 g = F/m therefor g also = g = GMm/mr2so g = GM/rr inside the earth as r becomes smaller the mass becomes smaller so g decreases draw a graph to show how g changes with r Authorghoran ID284478 Card Seta level physics Descriptionrevision Updated2014-09-30T09:04:21Z Show Answers