Question 1
Which way does gravity accelerate an orbiting satellite?
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Towards the centre of the orbit
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Away from the centre of the orbit
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In the direction of motion
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Opposite to the direction of motion
Question 2
Which equation links orbital speed \(v\), radius \(r\), and orbital period \(T\)?
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\(v = \frac{2\pi r}{T}\)
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\(v = 2\pi r T\)
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\(v = \frac{T}{2\pi r}\)
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\(v = \frac{r}{2\pi T}\)
Question 3
What keeps a satellite in orbit?
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Gravity
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Air resistance
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Earth's magnetism
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Electrostatic attraction
Question 4
Why does a satellite follow a curved orbit instead of falling straight down?
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Forward velocity combines with gravitational acceleration
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Outward velocity combines with air resistance
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Forward acceleration combines with magnetic attraction
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Upward velocity combines with electrostatic repulsion
Question 5
Which body orbits a planet rather than the Sun?
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A natural satellite
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A dwarf planet
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An asteroid
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A comet
Question 6
For a stable orbit around the same body, a change in orbital speed requires a change in what?
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The radius of the orbit
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The mass of the satellite
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The surface area of the satellite
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The direction of the orbit
Question 7
Light from a galaxy is red-shifted. What happened to its wavelength?
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Increased
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Decreased
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Unchanged
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Halved
Question 8
What is the force keeping an object moving in a circle called?
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Centripetal force
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Centrifugal force
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Resistance force
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Reaction force
Question 9
Which statement describes a star?
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A massive ball of hot plasma that releases energy by fusion
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A rocky object orbiting a planet
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A planet made mostly of gas
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A cloud of ice and dust orbiting the Sun
Question 10
Which main-sequence star is most likely to end in a supernova?
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Much more massive than the Sun
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The same mass as the Sun
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Much less massive than the Sun
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Not yet undergoing hydrogen fusion
Question 11
Why is a main-sequence star stable?
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Fusion's outward effect balances gravity
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Gravity has stopped acting
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The star has used all its hydrogen
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Its temperature has fallen to absolute zero
Question 12
Which term describes how fast stars move away from Earth (redshift)?
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Recessional velocity
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Orbital speed
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Escape velocity
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Spin velocity
Question 13
What does cosmic microwave background radiation support?
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A hot, dense beginning to the universe
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A cold, static beginning to the universe
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A universe formed around the Milky Way
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A universe whose expansion has stopped
Question 14
Where are elements heavier than iron formed?
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In supernovae
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In stable main-sequence stars
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In planets before stars form
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In cooling white dwarfs
Question 15
Why do astronauts feel weightless while orbiting Earth?
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They and their spacecraft are in free fall
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They are beyond Earth's gravitational field
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Their mass is converted into orbital energy
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Their spacecraft produces an upward force
Question 16
A satellite moves to a larger orbit at the same speed. What happens to its orbital period?
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It increases
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It decreases
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It stays the same
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It halves
Question 17
What pulls gas and dust together to form a protostar?
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Gravity
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Magnetic repulsion
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Radiation pressure
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Nuclear fission
Question 18
What happens to velocity during a circular orbit at constant speed?
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Its direction continually changes
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Its direction stays constant
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Its magnitude continually increases
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It becomes zero once per orbit
Question 19
Which object is a dwarf planet?
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Pluto
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Earth
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Sun
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Venus
Question 20
Which stage will the Sun enter after its main-sequence stage?
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Red giant
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Neutron star
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Supernova
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Black hole
Question 21
What does redshift in a distant galaxy's spectrum indicate?
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Moving away
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Moving toward us
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Remaining stationary
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Orbiting the Sun
Question 22
Which observation supports an expanding universe?
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More distant galaxies have greater redshifts
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More distant galaxies have smaller redshifts
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All galaxies have the same redshift
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Nearby galaxies have no spectral lines
Question 23
Which process involving hydrogen powers a main-sequence star?
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Nuclear fusion
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Nuclear fission
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Chemical combustion
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Radioactive decay
Question 24
What can a massive enough core form after a supernova?
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A black hole
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A white dwarf
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A main-sequence star
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A rocky planet
Question 25
Why are some telescopes placed in orbit rather than on the ground?
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The atmosphere blurs images
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They are closer to the stars
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Their mass is reduced
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Earth’s gravity is absent