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To which galaxy cluster does the Milky Way belong?

• The Milky Way Group

• The Andromeda Group

• The Local Group

• The Central Group

The reason that Ptolemy's geocentric model was accepted as the correct model of the universe from the time of the ancient Romans up until the Renaissance 1300 years later is that

• It had good predictive power

• It conformed to the religious doctrine

• It could explain retrograde motion

• All of the above

The reason planets exhibit retrograde motion is that

• Not all planets orbit the sun in the same sense (e.g., not all orbit counterclockwise)

• The planets all orbit the sun in the same sense but at different speeds

• The gravitational force of Jupiter causes planets to periodically reverse direction

• Planets are required to periodically reverse direction because of conservation of energy

Newton's laws of motion are inconsistent with the laws of electromagnetism because

• Newton's laws of motion allow you to catch up to light and make it stand still

• Newton's laws of motion define inertial mass but not gravitational mass

• Newton's laws of motion are valid only in accelerating reference frames

• Newton's laws of motion are valid only in inertial reference frames

Julie weighs 100 pounds. Now a cataclysmic event occus and the Earth shrinks to only 1/4 of its current radius while retaining the same mass. Now how much does Julie weigh?

• 25 pounds

• 100 pounds

• 400 pounds

• 1600 pounds

Galileo's discovery that Venus exhibits the full range of phases (crescent, full, new) showed that

• Venus orbits the sun and not the Earth

• Venus is closer to the sun than the Earth

• Venus exhibits retrograde motion

• Venus has a thick, reflective atmosphere

The distance to the Andromeda galaxy is about

• 2.5 light years

• 2.5 thousand light years

• 2.5 million light years

• 2.5 billion light years

The size of the visible universe is about

• 14 million light years

• 14 billion light years

• 46 billion light years

• 46 trillion light years

Suppose you are in a spaceship traveling at speed 0.99c towards the Earth. Your friend Betty is in front of you, traveling in the same direction as you but at the slightly lower speed of 0.98c. You fire a light beacon ahead fo you, towards Betty. At what speed does you light beacon pass Betty as observed from her reference frame?

• c

• 0.99c

• 0.98c

• 0.01c

You and your friend Juanita are both 22 years old. You travel to a nearby star system at speed 0.986c, corresponding to a gamma factor of 6, while Juanita stays on Earth. Upon reaching the star system, you immediately turn around and return to Earth, also traveling at 0.986c. When you return, you are 24 years old. How old is Juanita?

• 22 years old

• 28 years old

• 34 years old

• 42 years old