AST1002 Chapter 14 Test With
Complete Solution
Which one of the following statements is not a consequence of the
postulates of special relativity - ANSWER The wavelength emitted from a
source moving with respect to an observer is different from the wavelength
measured by an observer who is moving along with the source
How must an object be moving for us to be able to use the theory of special
relativity to describe the object - ANSWER The object must be moving at a
constant speed in a straight line; how fast it is moving is not important
Which of the following is a correct and complete statement of Einstein's first
postulate of special relativity - ANSWER Your description of physical reality is
the same regardless of the constant velocity at which you move
Suppose you are in a jet airliner traveling at a constant speed of 400 km/h in
a constant direction. All windows are blocked, so you cannot see outside, and
there are no vibrations from the engines. What experiment can you do to
determine that you are in fact moving - ANSWER None—all experiments will
give the same results that you would get when at rest on the ground
Suppose you are in the Space Shuttle in orbit around Earth at a speed of 7
km/s, and at some particular time your direction of travel is straight toward
the Sun. The speed of light in a vacuum is 300,000 km/s. What speed will you
measure for light from the Sun - ANSWER 300,000 km/s
Two spaceships are traveling past Earth at 90% of the speed of light in
opposite directions (i.e., they are approaching each other). One turns on a
, searchlight, which is seen by scientists aboard the other. What speed do the
scientists measure for this light (c = speed of light in a vacuum)? - ANSWER c
If you see an object moving past you at 90% of the speed of light, what will
its length appear to be - ANSWER The object will look shorter than if it were
at rest
Suppose you are in a spaceship traveling toward Earth at 95% of the speed of
light. Compared with when your ship was at rest on Mars, what length do
you measure for your spaceship - ANSWER same
Fred and Joanne both measure the length of a particular spaceship to be 100
m when it is on Earth. Joanne then gets into the spaceship and, after visiting
the Moon, hurtles past Earth at a speed close to the speed of light. Fred, still
on Earth, measures the length of the moving spaceship to be about 90 m. At
the same time, Joanne (using her own meterstick) measures the length of the
spaceship to be - ANSWER 100 m because she is "at rest" on the spaceship
Suppose you see a spaceship with a clock on it hurtling past you at 80% of
the speed of light. As it goes by, the second hand on the ship's clock ticks off
five seconds. How much time elapsed on your clock during this occurrence -
ANSWER more than 5 seconds
You are on Mars standing on the gangplank of your spaceship when you see
an identical spaceship go past Mars at 90% of the speed of light. When you
look closely at this spaceship, how does it compare with your own spaceship
- ANSWER The moving spaceship appears to be shorter than yours, and time
on it appears to move more slowly than on your ship
In a TV tube, the picture is created by a beam of electrons that travels down
the tube at a very high speed. What is the mass of one of these electrons,
Complete Solution
Which one of the following statements is not a consequence of the
postulates of special relativity - ANSWER The wavelength emitted from a
source moving with respect to an observer is different from the wavelength
measured by an observer who is moving along with the source
How must an object be moving for us to be able to use the theory of special
relativity to describe the object - ANSWER The object must be moving at a
constant speed in a straight line; how fast it is moving is not important
Which of the following is a correct and complete statement of Einstein's first
postulate of special relativity - ANSWER Your description of physical reality is
the same regardless of the constant velocity at which you move
Suppose you are in a jet airliner traveling at a constant speed of 400 km/h in
a constant direction. All windows are blocked, so you cannot see outside, and
there are no vibrations from the engines. What experiment can you do to
determine that you are in fact moving - ANSWER None—all experiments will
give the same results that you would get when at rest on the ground
Suppose you are in the Space Shuttle in orbit around Earth at a speed of 7
km/s, and at some particular time your direction of travel is straight toward
the Sun. The speed of light in a vacuum is 300,000 km/s. What speed will you
measure for light from the Sun - ANSWER 300,000 km/s
Two spaceships are traveling past Earth at 90% of the speed of light in
opposite directions (i.e., they are approaching each other). One turns on a
, searchlight, which is seen by scientists aboard the other. What speed do the
scientists measure for this light (c = speed of light in a vacuum)? - ANSWER c
If you see an object moving past you at 90% of the speed of light, what will
its length appear to be - ANSWER The object will look shorter than if it were
at rest
Suppose you are in a spaceship traveling toward Earth at 95% of the speed of
light. Compared with when your ship was at rest on Mars, what length do
you measure for your spaceship - ANSWER same
Fred and Joanne both measure the length of a particular spaceship to be 100
m when it is on Earth. Joanne then gets into the spaceship and, after visiting
the Moon, hurtles past Earth at a speed close to the speed of light. Fred, still
on Earth, measures the length of the moving spaceship to be about 90 m. At
the same time, Joanne (using her own meterstick) measures the length of the
spaceship to be - ANSWER 100 m because she is "at rest" on the spaceship
Suppose you see a spaceship with a clock on it hurtling past you at 80% of
the speed of light. As it goes by, the second hand on the ship's clock ticks off
five seconds. How much time elapsed on your clock during this occurrence -
ANSWER more than 5 seconds
You are on Mars standing on the gangplank of your spaceship when you see
an identical spaceship go past Mars at 90% of the speed of light. When you
look closely at this spaceship, how does it compare with your own spaceship
- ANSWER The moving spaceship appears to be shorter than yours, and time
on it appears to move more slowly than on your ship
In a TV tube, the picture is created by a beam of electrons that travels down
the tube at a very high speed. What is the mass of one of these electrons,
