Module 5.4 Flashcards
Escape Velocity
The minimum velocity required by an object to be able to
escape a gravitational field of a mass when projected vertically from its surface
Field Lines
A line representing the path that a mass would take when placed
within the field
Geostationary Satellite
A satellite that orbits above the equator with a 24 hour
period, so it will always remain above the same position on the Earth. They orbit
approximately 36,000km above the surface of the Earth.
Gravitational Field Strength
The force per unit mass exerted on a small test
mass placed within the field.
Gravitational Field
A region surrounding a mass in which any other object with
mass will experience an attractive force
Gravitational Potential Energy
The component of an object’s energy due to its
position in a gravitational field
Gravitational Potential
The work done per unit mass required to move a small
test mass from infinity to that point.
Kepler’s First Law
All planets travel in elliptical orbits, centered around the sun
Kepler’s Second Law
All planets sweep out the same area in a given period of
time.
Kepler’s Third Law
The square of a planet’s period is directly proportional to the
cube of its mean distance to the sun
Newton’s Law of Gravitation
The force between two masses is proportional to
the product of the masses involved and inversely proportional to the square of the
separation of the masses
escape velocity formula
1/2 (mv^2) = GMm/r
v^2 = 2GM/2
What is the max gravitational potential energy
0J
Derive Kepler’s third law
1) Equate mv^2/r = GMm/(r^2)
2) rearrange for GM/r = v^2
3) Velocity of circular motion can be written as v = 2π r/T because velocity is displacement over time.
4) sub in to 2nd equation
GM/r = (4π^2 r^2)/t^2
5) Rearrange to show that
T^2 = (4π^2 r^2)/GM
Therefore T^2 is proportional to r^3
Satellites
are objects that orbit other, larger objects
Give 3 examples of uses of satellites
- communications,
- scientific research,
- Global Positioning Systems (GPS).
What are the 2 types of satellites and give an example
- Natural satellites e.g the moon
- artificial satellites e.g satellites humans have sent to space
What are the 3 things that geostationary orbits have in common
- Orbital period of 1 day
- They travel in the same direction as the rotation of the Earth, along the equatorial plane
- They remain above the same point on the Earth’s surface.
