astrophysics Flashcards

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1
Q

what happens when stars start to run out of hydrogen?
-what happens to red giant

A

-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

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2
Q

what is an orbit

A

a curved path of one celestial obj / spacecraft around another celestial obj

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3
Q

what is newtons first law

A

an object travelling at a certain velocity will keep travelling at that velocity unless acted upon by a resultant force

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4
Q

what contributes to a steady orbit?

A
  • large gravitational pull
    -instantaneous velocity
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5
Q

relationship betw obj and velocity and acceleration in an orbit

A

the obj is accelerating bcs the velocity is changing

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6
Q

what needs to happen if an orbiting object is pulled closer

A

-magnitude of velocity must increase

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7
Q

difference betw comets and asteroids

A

-asteroids: made up mainly of rock and metal
-comets: mainly ice and dust

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8
Q

Explain why the star is stable while it is in the main sequence stage of its life cycle.

A

gravitational force inwards and forces as a result of fusion reactions outwards

are in equilibrium / balanced

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9
Q

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.

A

expand to become a red giant

collapse to become a white dwarf

cools to become a black dwarf

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10
Q

Explain why the velocity of the satellite changes as it orbits the Earth.

A

(force of) gravity causes the satellite to accelerate (towards the Earth)

the acceleration causes a change in direction

velocity changes because direction changes

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11
Q

Explain why a star remains stable.
(2)

A

expansion due to fusion energy

in equilibrium with gravitational collapse

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12
Q

what condition needs to be followed so a wire can induce a current

A

wire has to be part of a complete circuit

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13
Q

difference between alternator and dynamo (on a graph)

A

alternator changes polarity, dynamo does not

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