5.1.2 - Out into space (A-Level Physics OCR B H557)

#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 $V_{grav} = \dfrac{E_{grav}}{m} = -\dfrac{GM}{r}$

A-Level Physics OCR B H557

5.1.2: Out into space