astrophysics Flashcards
what happens when stars start to run out of hydrogen?
-what happens to red giant
-no more nuclear fusion, becomes red giant (red bcs surface of star cool)
-fusion of helium and other elements occur
heavier elements like iron created in the core of the star
what is an orbit
a curved path of one celestial obj / spacecraft around another celestial obj
what is newtons first law
an object travelling at a certain velocity will keep travelling at that velocity unless acted upon by a resultant force
what contributes to a steady orbit?
- large gravitational pull
-instantaneous velocity
relationship betw obj and velocity and acceleration in an orbit
the obj is accelerating bcs the velocity is changing
what needs to happen if an orbiting object is pulled closer
-magnitude of velocity must increase
difference betw comets and asteroids
-asteroids: made up mainly of rock and metal
-comets: mainly ice and dust
Explain why the star is stable while it is in the main sequence stage of its life cycle.
gravitational force inwards and forces as a result of fusion reactions outwards
are in equilibrium / balanced
Describe what will happen to the star between the main sequence stage and the end of the star’s life cycle.
You should include the names of the stages in the life cycle of the star.
expand to become a red giant
collapse to become a white dwarf
cools to become a black dwarf
Explain why the velocity of the satellite changes as it orbits the Earth.
(force of) gravity causes the satellite to accelerate (towards the Earth)
the acceleration causes a change in direction
velocity changes because direction changes
Explain why a star remains stable.
(2)
expansion due to fusion energy
in equilibrium with gravitational collapse
what condition needs to be followed so a wire can induce a current
wire has to be part of a complete circuit
difference between alternator and dynamo (on a graph)
alternator changes polarity, dynamo does not
