Einstein's Theory of Realtivity
Circle the letter of each sentence that is true about motion and frames of reference. (a) All motion is relative. (b) All frames of reference are arbitrary. (c) A spaceship can measure its speed relative to other objects. (d) A spaceship's speed must be measured relative to other objects.
(a) (b) (d)
Circle the letter of each sentence that is true about space and time travel. (a) Time for a person on Earth and time for a person in high-speed spaceship are not the same. (b) A person's heart beats to the rhythm of the realm of Earth time. (c) The amount of energy required to propel spaceships to relativistic speeds are ten times the energy used to put the space shuttles into orbit. (d) Time travels only one way- forward.
(a) (d)
Circle the letter of each sentence that is true about the traveling twin. (a) If the traveling twin maintains a speed of 50% the speed of light for one year (according to the clocks on the spaceship), 1 year will have lapsed on Earth. (b) If the traveling twin maintains a speed of 87% the speed of light for one year (according to the clocks on the spaceship), 2 years will have passed on Earth. (c) If the traveling twin maintains a speed of 99.5% the speed of light for one year (according to the clocks on the spaceship), 10 years will have lapsed on Earth. (d) The traveling twin experiences three frames of reference on his round trip away from and back to Earth.
(b) (c)
Consider an object with a length at rest of 6 meters. When it approaches the speed of light, and observer at rest would measure its length approaching what value? (a) 0m (b) 7m (c) 10m (d) 100m
0m
Explain what the graph below says about one second on a stationary clock as measured on a moving clock. time / I__________/ I_________________ Speed
1 second on a stationary clock sketched and as measures on a moving clock.
Traveling at the speed of light, how long would it take a person to reach the center of our galaxy?
30,000 years
Einstein concluded that if an observer could travel close to the speed of light, he would measure the light as moving away from him at _________________.
300,000 km/s
What is the speed of light in the light clock?
300,000 km/s
A baseball is moving horizontally. Describe how the shape of the baseball changes as the relative speed between the baseball and an observer increases.
It becomes thinner, perpendicular direction lengths do not change.
What do the variables L and L0 represent?
L- Length contraction L0- Original Length
Write the equation for the the relationship betweeen L and L0.
L=L0(square root(1-(v^2/c^2))
What is another name for fundamental assumption?
Postulates
Explain why the occupants of each of the spaceships in their figure below will be unable to determine who is moving and who is at rest. D--> D--> d d
Space person B is not moving and space person A is going quickly, but space person A is moving and it looks like person B is moving towards them, so person A would seem to get slower.
What is the first postulate of special relativity?
States that all the laws of nature are the smae in all uniformly moving frames of reference.
A moving spaceship contains a light clock. An observer is at rest with respect to the spaceship. How do the flashes of light from the light clock appear to move to the observer?
They observe the flash moving along a *diagonal* path.
True or False: In designing the global positioning system (GPS), which can pinpoint positions on Earth to within meters, scientists and engineers had to accommodate for relativistic time dilation.
True
True or False: Time dilation occurs ever so slightly for everyday speeds but significantly for speeds approaching the speed of light.
True
True or False: Whenever we move through space, we to some degree alter our rate of moving into the future, which is called time dilation.
True
A person moving a train shines a flashlight in the direction that the train is moving. Does an observer standing as rest outside of the train measure the speed of light as faster, slower, or the same speed as when the train is not moving?
same
From the viewpoint of special relativity, you travel through a combination of _________________ and _________________.
space and time
The ratio of ________________ to _______________ for light is the same for all who measure it.
space and time
Einstein's __________________ describes how time is affected by motion in space at constant velocity and how mass and energy are related.
special theory of relativity
Write the equation for the relationship between the time t0 (proper time) in the observer's own frame of reference and the relative time measures in another frame of reference.
t= (t0)/( square root(1-v/c)^2)
What variable is used to indicate the value of the speed of light for all observers?
C
Why are the practicalities of long space journeys prohibitive?
The amount of energy required to propel spaceships to relativistic speeds are billions of times the energy used to put space shuttles into orbit shielding radiation induced by high speeds.
In which direction does a spaceship contract?
The direction of motion
A moving space ship contains a light clock. How do flashes of light from the light clock appear to move to an observer inside the spaceship?
The light flash appear to move *vertically*.
What is the second postulate of special relativity?
The speed of light in empty space will always have the same value regardless of the motion of the source of motion of the observer.
What is length contraction?
When an object moves at very high speed relation to an observer, its measures length in the direction of motion.
According to the special theory of relativity, how do standing still and traveling at the same speed of light differ?
When standing, time passes so you travel through time, but when traveling at the speed of light, you travel with light, time does not pass.
