Question 1

Why do astronauts in space appear to feel no pull of gravity?

Accepted Answer

A)  There is no gravity in space. 
B)  Gravity happens only when objects are accelerating. 
C)  In space, the gravity from the Moon and the Sun cancels out Earth's gravity. 
D)  They and their spaceship are both freely falling at the same rate in the gravitational field. 
E)  The astronauts do not have any mass when they are in space. 
A)  There is no gravity in space. 
B)  Gravity happens only when objects are accelerating. 
C)  In space, the gravity from the Moon and the Sun cancels out Earth's gravity. 
D)  They and their spaceship are both freely falling at the same rate in the gravitational field. 
E)  The astronauts do not have any mass when they are in space.

Question 2

What is the meaning of the word spacetime?

Accepted Answer

A)  It is a mental framework for keeping track of numbers in Newtonian physics. 
B)  Space and time form a two-dimensional region where physics takes place. 
C)  The term has no special meaning; it's just a fancy way to sound important when talking about physics. 
D)  It is the combined treatment of space and time in the theory of relativity. 
E)  It is the idea that observers will always measure the same locations and times of events. 
A)  It is a mental framework for keeping track of numbers in Newtonian physics. 
B)  Space and time form a two-dimensional region where physics takes place. 
C)  The term has no special meaning; it's just a fancy way to sound important when talking about physics. 
D)  It is the combined treatment of space and time in the theory of relativity. 
E)  It is the idea that observers will always measure the same locations and times of events.

Question 3

Explain how Newtonian physics can be considered an approximation to relativity.

Accepted Answer

Newtonian physics explains many phenomen

Question 4

An external observer watches a spacecraft accelerate.In the spaceship's frame of reference, it is accelerating at a constant acceleration of
g.Which of the situations shown in the figure below will the external observer see for the spaceship's velocity with time, and why?

Accepted Answer

The external observer will see the lower

Question 5

If the Lorentz factor is 2, what is the corresponding speed?

Accepted Answer

A)  0.86c 
B)  1.55c 
C)  0.27c 
D)  0.52c 
E)  0.9999c 
A)  0.86c 
B)  1.55c 
C)  0.27c 
D)  0.52c 
E)  0.9999c

Question 6

Suppose we discovered radio signals coming from the star Alpha Centauri, which is 4.4 light-years from us, and we sent a crew in a spacecraft to visit it.If the spacecraft used revolutionary technology allowing it to travel at a speed of 0.5c, how long would it take the spacecraft to get to Alpha Centauri, and how much time would the astronauts say passed during the trip? (Ignore the time it would take to accelerate the spacecraft to reach a velocity of 0.5c.)

Accepted Answer

Traveling at a speed of 0.5c,the time it

Question 7

Stellar aberration should be distinguished from stellar parallax in that

Accepted Answer

A)  stellar aberration immediately allows for measurements of distances to stars. 
B)  stellar parallax is easily observable, whereas aberration is impossible to measure. 
C)  stellar aberration depends on Earth's orbital speed around the Sun. 
D)  stellar parallax depends on Earth's orbital speed around the Sun. 
E)  stellar aberration demonstrates that the speed of light is infinite. 
A)  stellar aberration immediately allows for measurements of distances to stars. 
B)  stellar parallax is easily observable, whereas aberration is impossible to measure. 
C)  stellar aberration depends on Earth's orbital speed around the Sun. 
D)  stellar parallax depends on Earth's orbital speed around the Sun. 
E)  stellar aberration demonstrates that the speed of light is infinite.

Question 8

Describe two possible ways to make a stellar-size black hole.

Accepted Answer

Black holes can be made in supernova exp

Question 9

You are driving on an interstate at 70 mph and, in the adjacent lane but moving in the opposite direction, another car is zipping by.From your point of view, the other car seems to pass at 150 mph, which would seem crazy.What is the speed that the odometer should indicate inside the other car?

Accepted Answer

A)  80 mph 
B)  55 mph 
C)  220 mph 
D)  110 mph 
E)  150 mph 
A)  80 mph 
B)  55 mph 
C)  220 mph 
D)  110 mph 
E)  150 mph

Question 10

An astronaut traveling at very high speeds to Proxima Centauri, which is 4.3 light-years from Earth, would arrive in fewer than 4.3 years, from his or her perspective.This is because

Accepted Answer

A)  he or she can travel faster than the speed of light. 
B)  a light-year is longer than the distance light travels in 1 year. 
C)  radioactive particles (muons) will interfere with the astronaut's clock. 
D)  Proxima Centauri appears to be farther than it is due to the travel time of light. 
E)  the astronaut will measure a shorter distance than 4.3 light-years. 
A)  he or she can travel faster than the speed of light. 
B)  a light-year is longer than the distance light travels in 1 year. 
C)  radioactive particles (muons) will interfere with the astronaut's clock. 
D)  Proxima Centauri appears to be farther than it is due to the travel time of light. 
E)  the astronaut will measure a shorter distance than 4.3 light-years.

Question 11

General relativity predicts that coalescing (merging) massive objects would trigger

Accepted Answer

A)  pulses of electromagnetic radiation. 
B)  gravitational waves. 
C)  high-energy particles. 
D)  a slowing of clocks here on Earth. 
E)  blueshifted light from the surface of the object. 
A)  pulses of electromagnetic radiation. 
B)  gravitational waves. 
C)  high-energy particles. 
D)  a slowing of clocks here on Earth. 
E)  blueshifted light from the surface of the object.

Question 12

The bending of light paths near a massive object is the essence of

Accepted Answer

A)  time dilation. 
B)  the twin paradox. 
C)  gravitational lensing. 
D)  length contraction. 
E)  mass increase. 
A)  time dilation. 
B)  the twin paradox. 
C)  gravitational lensing. 
D)  length contraction. 
E)  mass increase.

Question 13

A person would experience ________ as he or she approached the event horizon of a Solar-mass black hole.

Accepted Answer

A)  extremely strong tidal forces 
B)  flash freezing 
C)  strong Hawking radiation 
D)  strong infrared radiation 
E)  nothing 
A)  extremely strong tidal forces 
B)  flash freezing 
C)  strong Hawking radiation 
D)  strong infrared radiation 
E)  nothing

Question 14

You are driving on an interstate at 70 mph and, in the adjacent lane and moving in the same direction, another car is passing you.From your point of view, the other car seems to advance at 10 mph (i.e., it is only slowly moving ahead of you).What is the speed that the odometer should indicate inside the other car?

Accepted Answer

A)  70 mph 
B)  10 mph 
C)  80 mph 
D)  60 mph 
E)  75 mph 
A)  70 mph 
B)  10 mph 
C)  80 mph 
D)  60 mph 
E)  75 mph

Question 15

In the figure below, an observer in the spaceship on the right would observe the light emitted by the spaceship on the left as traveling at ________ and with ________ frequency than which it was emitted.

Accepted Answer

A)  c; a lower 
B)  c; a higher 
C)  1.5c; the same 
D)  1.5c; a lower 
E)  1.5c; a higher 
A)  c; a lower 
B)  c; a higher 
C)  1.5c; the same 
D)  1.5c; a lower 
E)  1.5c; a higher

Question 16

Explain the relativistic effects on clocks aboard the International Space Station compared with synchronized clocks here on Earth.

Accepted Answer

There are two competing effects that wou

Question 17

Explain why Einstein's theory of general relativity predicts the existence of gravitational lensing.

Accepted Answer

Einstein's theory of general relativity

Question 18

A 15-MSUN star that has been monitored for decades is found to be orbiting in a highly eccentric ellipse about an unseen mass (presumably a supermassive black hole) at the center of Milky Way with a period of 15.6 years and a semimajor axis of about 1,000 AU.What is the mass of the unseen object?

Accepted Answer

According to Newtonian version of the th

Question 19

The detection of gravitational waves is important evidence for

Accepted Answer

A)  the existence of neutron stars. 
B)  general relativity. 
C)  the Big Bang. 
D)  Type II supernovae. 
E)  Newton's law of gravitation. 
A)  the existence of neutron stars. 
B)  general relativity. 
C)  the Big Bang. 
D)  Type II supernovae. 
E)  Newton's law of gravitation.

Question 20

The gravitational redshift of light should be smallest for light emitted from the surface of

Accepted Answer

A)  a black hole. 
B)  the Sun. 
C)  a white dwarf. 
D)  a planet similar to Earth. 
E)  a neutron star. 
A)  a black hole. 
B)  the Sun. 
C)  a white dwarf. 
D)  a planet similar to Earth. 
E)  a neutron star.

Exam 18: Relativity and Black Holes

Why do astronauts in space appear to feel no pull of gravity?

What is the meaning of the word spacetime?

Explain how Newtonian physics can be considered an approximation to relativity.

An external observer watches a spacecraft accelerate.In the spaceship's frame of reference, it is accelerating at a constant acceleration of g.Which of the situations shown in the figure below will the external observer see for the spaceship's velocity with time, and why?

If the Lorentz factor is 2, what is the corresponding speed?

Stellar aberration should be distinguished from stellar parallax in that

Describe two possible ways to make a stellar-size black hole.

You are driving on an interstate at 70 mph and, in the adjacent lane but moving in the opposite direction, another car is zipping by.From your point of view, the other car seems to pass at 150 mph, which would seem crazy.What is the speed that the odometer should indicate inside the other car?

An astronaut traveling at very high speeds to Proxima Centauri, which is 4.3 light-years from Earth, would arrive in fewer than 4.3 years, from his or her perspective.This is because

General relativity predicts that coalescing (merging) massive objects would trigger

The bending of light paths near a massive object is the essence of

A person would experience ________ as he or she approached the event horizon of a Solar-mass black hole.

In the figure below, an observer in the spaceship on the right would observe the light emitted by the spaceship on the left as traveling at ________ and with ________ frequency than which it was emitted.

Explain the relativistic effects on clocks aboard the International Space Station compared with synchronized clocks here on Earth.

Explain why Einstein's theory of general relativity predicts the existence of gravitational lensing.

A 15-MSUN star that has been monitored for decades is found to be orbiting in a highly eccentric ellipse about an unseen mass (presumably a supermassive black hole) at the center of Milky Way with a period of 15.6 years and a semimajor axis of about 1,000 AU.What is the mass of the unseen object?

The detection of gravitational waves is important evidence for

The gravitational redshift of light should be smallest for light emitted from the surface of

Thinking Like an Astronomer

Patterns in the Skymotions of Earth and the Moon

Motion of Astronomical Bodies

Gravity and Orbits

Light

The Tools of the Astronomer

The Formation of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquidthe Giant Planets

Planetary Moons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

Our Starthe Sun

The Interstellar Medium and Star Formation

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

Galaxies

The Milky Waya Normal Spiral Galaxy

The Expanding Universe

Cosmology

Large-Scale Structure in the Universe

Life

Filters

In the figure below, an observer in the spaceship on the right would observe the light emitted by the spaceship on the left as traveling at and with frequency than which it was emitted.

A 15-M_SUN star that has been monitored for decades is found to be orbiting in a highly eccentric ellipse about an unseen mass (presumably a supermassive black hole) at the center of Milky Way with a period of 15.6 years and a semimajor axis of about 1,000 AU.What is the mass of the unseen object?