Astro100 Exam 2 Answer Key

The astronomer put on trial for his advocating the heliocentric model was

Galileo

Think about the Earth's precession. The star Thuban was the North Star in 4500 B.C.E. When will it next be the North Star?

In the year 21,500 CE

Which of the following lists the men in the order in which they lived?

Aristotle, Ptolemy, Copernicus, Galileo, Newton

The point at which the Earth is closest to the Sun is called

Perihelion

Theoretically, Newton showed things can orbit (in general) in (choose all that apply):

Circles Ellipses Parabolae Hyperbolae

Why is Polaris unique? (Check all that apply.)

It remains stationary

The astronomer who revived the heliocentric model around 1512 was

Nicolaus Copernicus.

Acceleration is (accept all that apply):

the change in velocity. equal to net force on an object divided by mass

Suppose the distance between two objects in a gravitational interaction were reduced to one-third of the original. The resultant gravity between the two objects would be

9 times the original

The geocentric model was accepted for so long because (choose all that apply):

It made accurate, verifiable predictions It appealed to "common sense" It was supported by the Roman Catholic Church The few things that could disprove the model were beyond the Earth's technology for centuries It was supported by the physics of Aristotle

The astronomer who formulated the laws of planetary motion from Tycho's data was

Kepler

Which of the following planets would it be impossible to see from Venus at midnight (Venus time)? (Choose all that apply.)

Mercury

A freight train breaks down on a rickety bridge over a deep chasm. Suddenly, the bridge gives way, and the train plummets toward the ground below. Alarmed, the engineer of the train allows the pipe he has been smoking to be released from his lips. It will

Seem to float in front of him

Where on the Earth would you have to be to be able for Polaris to be at your nadir?

The South Pole

Two spaceships that have different masses but rocket engines of identical force are at rest in space. If they fire their rockets at the same time, which ship will speed up faster?

The one with the lower mass.

Why, according to Aristotle, do objects in the heavens behave differently from objects on Earth? (Choose all that apply.)

They are made of a different element; they are perfect.

Which of the following accurately describes the orbital motions of the planets?

They sweep out equal areas in equal times

Suppose a heavy anvil and a feather are dropped from the top of a mountain on the moon. What will happen?

They will impact the lunar surface at the same time.

Suppose you are an astronaut taking a spacewalk alongside the space shuttle to make a repair on it with a hammer. Your life-line breaks and the jets on your backpack do not work. How can you get back to the space shuttle safely?

Throw your hammer away from the ship.

Think about your computer, which is at this moment pressing down on the surface on which it's resting. Does the surface exert a force upwards on the computer?

True

The statement that astronauts on the Moon are weightless is

false because the Moon exerts a gravitational force on their bodies.

Suppose there were another planet between Mars and Jupiter. Which of the following statements would be true ? (Choose all that apply.)

its "year" would be longer than Earth's.