Gravitational (M5)

Question 1

Gravitational potential

Answer 1

The work done per unit mass to bring an object from infinity to a point in the gravitational field.
Symbol: Vg
Unit: Jkg^-1
Vg = -GM/r

Question 2

Gravitational potential energy

Answer 2

The capacity for work as a result of an object’s position in a gravitational field.
Symbol: E
Unit: J
E = mgh
E = mVg

Question 3

Gravitational field

Answer 3

A field created around any object with mass, extending all the way to infinity but diminishing as the distance from the centre of mass of the object increases.

Question 4

Gravitational field strength

Answer 4

The gravitational force exerted per unit mass at a point within a gravitational field.
Symbol: g

Question 5

Gravitational field lines

Answer 5

Lines of force used to map the gravitational field pattern around an object with mass.

Question 6

Radial field

Answer 6

A symmetrical field that diminishes with distance squared from its centre, such as the gravitational field around a spherical mass, or the electrical field around a spherical charged object.

Question 7

Point mass

Answer 7

A mass with negligible volume

Question 8

Uniform gravitational field

Answer 8

A gravitational field in which the field lines are parallel and evenly spaced, and the value of g remains constant.

Question 9

Newton’s law of gravitation

Answer 9

The force between two points masses is directly proportional to the product of the mass and inversely proportional to the square of the separation between them.
F = -GMm/r^2

Question 10

Gravitational constant G

Answer 10

The constant in Newton’s Law of Gravitation with a value determined from experimentation.
Value = 6.67x10^-11 Nkg^-2m^2

Question 11

Escape velocity

Answer 11

KE = 1/2 mvv
GPE = GMm/r

1/2 mvv = GMm/r
1/2 vv = GM/r
vv = 2GM/r
v = rt(2GM/r)