Gravitation Flashcards
What is meant by the gravitational potential of a point in space
The work done by external forces to move unit mass from infinity to that point
What Is a light year
The distance light will travel in one year
What is astronomical unit
Is the average distance between the earth’s and the sun
What is the symbol for gravitational potential
V
What effect does infinity have
No effect
What does gravitational potential allow us to workout
It allows us to calculate how much engery is required to move between points
What happens to the work done first you take a different path
The work done will be the same as it is always conserved
How do black holes form
From the death of a star
What is the singularity of a black hole
Single point of infinite matter
What is the symbol for angular velocity
W or omega
Gravitational difference
Final - start
Units for gravitational potential
Jkg-1
At whixh point is gravitational potential theoretically zero
At infinity
What is meant hur the term Conservative field
Work done by the mass when moving to one point to another in a gravitational field is zero
At which one is the gravitational potential theoretical zero
At infinity
What is meant by conservative feild
Work done by the mass when moving to one point to another in gravitational fried is zero
What does the mass determine in regards to star
It will determine the life time of a star
The heavy star the faster it evolves
What is luminosity
The total power of a star across the electromagnetic spectrum
Apparent brightness
A measure of the star brightness as viewed from earth
What temperature are blue star
High surface temperature
What temperature are red stara
Low temperature
From nebula to main sequence
A super novoa or a movement of large objects causes the gravitational force to overcome the thermal pressure that is acting outwards.
This will continue until the nebula because hot enough for the fusion to begin
Once the fusion happens the thermal pressure and gravitational force balance out creating the star.
Proton - proton chain
Protium + Protium (11H) -> hydrogen + positron and electron neutrino
Hydrogen + protium -> helium 3 (21He) + gamma (y)
Helium 3 + helium 3 -> helium 4 + 2protium
Star - red giant
Hydrogen fusion in the core of a main sequence star supplies the engery that maintains the star outwards thermal pressure to balance inward gravitational forces.
When the Hydrogen in the core becomes depleted nuclear fusion in the core ceases, the surrounding the care however it will still contain Hydrogen
Gravitational forced cause both the core and the surrounding shell of Hydrogen to shrink
In a star like the sun, the Hydrogen shell becomes hot enough for the Hydrogen fusion on the star
This leads to an increase in power which pushes the surface of the star outwards casting it to cool. At thus stage it will br a gaint or super giant star.
Colou4 order of the hertzpring - Russell diagram
Blue white yellow orange red
What is the gravitational field strength
Gravitational force acting on a unit mass
Why is engery conserved
Since the engery required to move mass between two points In a gravitational field is independent of the path taken
As a probe travels further away from earth what will happen to the time
Faster
As it is in a weaker gravitational field
Light years to meters
365x60x60x24
Suggest why a staliite is low orbit will loose enegery at a greater rate then in a high altitude orbit
Greater drag from the atmosphere
