#5.1.2a(i)
changes of gravitational and kinetic energy
#5.1.2a(ii)
motion in a uniform gravitational field
#5.1.2a(iii)
the gravitational field and potential of a point mass
modelling the mass of a spherical object as a point mass at its centre
#5.1.2a(iv)
angular velocity in rad s–1
#5.1.2a(v)
motion in a horizontal circle and in a circular gravitational orbit.
#5.1.2b
Make appropriate use of:
(i) the terms: force, kinetic and potential energy, gravitational field, gravitational potential, equipotential surface
by sketching and interpreting:
(ii) graphs showing gravitational potential as area under a graph of gravitational field versus distance, graphs showing changes in gravitational potential energy as area under a graph of gravitational force versus distance between two distance values
(iii) graphs showing force as related to the tangent of a graph of gravitational potential energy versus distance, graphs showing field strength as related to the tangent of a graph of gravitational potential versus distance
(iv) diagrams of gravitational fields and the corresponding equipotential surfaces.
#5.1.2c(i)
uniform gravitational field, gravitational potential energy change = \(mgh\)
Learners will also be expected to recall this equation
#5.1.2c(ii)
energy exchange, work done, \(∆E = F∆s \); no work done when the force is perpendicular to the displacement, resulting in no work being done whilst moving along equipotentials
#5.1.2c(iii)
\(a = \dfrac{v^2}{r} \),
\(F = \dfrac{mv^2}{r} = mrω^2\)
#5.1.2c(iv)
the radial components:
\(F_{grav} = -\dfrac{GmM}{r^2}\),
\(g = \dfrac{F_{grav}}{m} = -\dfrac{GM}{r^2}\)
#5.1.2c(v)
gravitational potential energy
\(E_{grav} = -\dfrac{GMm}{r}\)
#5.1.2c(vi)
gravitational potential
\(V_{grav} = \dfrac{E_{grav}}{m} = -\dfrac{GM}{r}\)