Module 4 - Gravitation Section 3.4.2

3.4.2 Gravitation Section:

Multiple choice Structured questions
Syllabus Extract You should be able to:

Newton's law

Gravity as a universal attractive force acting between all matter.

Force between point masses

where G is the gravitational constant.

Remember that gravitational force is one of the four fundamental forces.

It is only an attractive force.

Acts between masses.

Is an inverse square relationship

Gravitational field strength

Concept of a force field as a region in which a body experiences a force.

Representation by gravitational field lines.

g as 'force per unit mass' defined by:

Magnitude of g in a radial field given by:


Gravitational potential

Understanding of the definition of gravitational potential, including zero value at infinity, and of gravitational potential difference.

Work done in moving mass m given by

Magnitude of V in a radial field given by:

Graphical representations of variations of g and V with r.

V related to g by:

Gravitational potential is energy...

Remember that measurements are from the centres of mass - strictly speaking the masses should be point masses.

Orbits of planets and satellites

Orbital period and speed related to radius of circular orbit.

Energy considerations for an orbiting satellite.

Significance of a geosynchronous orbit.

You do not need Kepler's Laws - but they are good for your soul...