The person who first determined that planets move in elliptical orbits

• Kepler

• Copernicus

• Aristarchus

• Galileo

• Anaximander

Newton's laws of motion are valid

• Only in an inertial rest frame and for speeds much less than c

• Only in an inertial rest frame but for all speeds, even those near c

• In all frames, accelerating or not

• Only for objects near the surface of the Earth

The first measurement of the speed of light was performed by

• Ole Roemer, using observed variations in th eorbital period of Jupiter's moon Io

• Ole Roemer and an assistant, using lantern light from separated hilltops

• Galileo, using a rotating mirror reflecting light back-and-forth to a stationary mirror

• Foucault, using a rotating mirror reflecting light back-and-forth to a stationary mirror

• Galileo and an assisstant, using lantern light from separated hilltops

Which of the following is correct concerning an electromagnetic wave?

• The electric and magnetic fields point perpendicularly to each other and to the direction of propagation of the wave

• The electric and magnetic fields both point parallel to the direction of propagation of the wave

• The electric and magntic fields point in the same direction as each other, which is perpendiculat to the direction of propagration of the wave

• The electric and magnetic fields both point opposire to the direction of propagation of the wave

By the gravitational mass of an object, we mean the quantity that

• Tells you how heavy an object is

• Tells you how difficult it is to get an object moving

• Explains why objects in free-fall at the same rate "g"

• Explains why an object at rest will stay at rest unless acted upon by a force

Einstein's theory of special relativity is valid

• Only in inertial reference frames

• Only for speeds much less than the speed of light

• Only for speeds near the speed of light

• Only in accelerating reference frames

• Only in small gravitational fields

How far away is Proxima Centauri, the nearest star?

• 4 light years

• 46 billion light years

• 14 billion light years

• 2.5 million light years

• 20 billion light years

The main reason Ptolemy introduces epicylces into his geocentric model was to

• Explain why planets were observed to sometimes stop and reverse their motion

• Explain why planets are observed to vary in brightness

• Describe the effects of an ellipitical orbit

• Explain why the observed orbital periods if Jupiter's moons vary

As Earth moves away from Saturn during Earth's orbit around the sun, the observed orbital periods of Saturn's moons become longer because

• of the the finite speed of light

• the gravitational force between Earth and Saturn decreases

• Earth's orbital speed decreases

• Earth's orbital speed increases

• the speed of Io's orbital motion around Saturn increases

Galileo's observation of the phases of Venus

• Showed that Venus orbits around the sun

• Showed that Venus has a thick atmosphere

• Showed that Venus is closer to the sun than Earth

• Showed that Venus has a larger orbital speed than Earth

• Showed that Venus does not have a magnetic field