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Online Course Support | Understanding Einstein: The Special Theory of Relativity

If Alice travels from Earth to the center of the galaxy in ten (10) years, and the distance to the center of the galaxy in the Earth frame of reference is 30,000 light years, how far is it (approximately) from Earth to the center of the galaxy from her perspective?
ByAdmin July 28, 2021July 29, 2021

1. Question 1 If Alice travels from Earth to the center of the galaxy in ten (10) years, and the distance to the center of the galaxy in the Earth…

Read More If Alice travels from Earth to the center of the galaxy in ten (10) years, and the distance to the center of the galaxy in the Earth frame of reference is 30,000 light years, how far is it (approximately) from Earth to the center of the galaxy from her perspective?
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In the twin paradox example done in lecture, just after Alice leaves the star on her return trip (and she’s back up to her cruising speed of 0.6c), she observes Bob’s clock back where he is located. (In other words, she has a photo taken of his clock and her corresponding clock at that location, her clock being part of her lattice of clocks.) Compared to her clock, does she observe Bob’s clock to be behind, ahead, or the same time as hers?
ByAdmin July 28, 2021July 29, 2021

9. Question 9 In the twin paradox example done in lecture, just after Alice leaves the star on her return trip (and she’s back up to her cruising speed of…

Read More In the twin paradox example done in lecture, just after Alice leaves the star on her return trip (and she’s back up to her cruising speed of 0.6c), she observes Bob’s clock back where he is located. (In other words, she has a photo taken of his clock and her corresponding clock at that location, her clock being part of her lattice of clocks.) Compared to her clock, does she observe Bob’s clock to be behind, ahead, or the same time as hers?
Online Course Support | Understanding Einstein: The Special Theory of Relativity

In the lecture on “Spaceships on a rope,” the reason that the rope breaks according to the perspective of the stationary observer (A) is:
ByAdmin July 28, 2021July 29, 2021

5. Question 5 In the lecture on “Spaceships on a rope,” the reason that the rope breaks according to the perspective of the stationary observer (A) is: 1 point …

Read More In the lecture on “Spaceships on a rope,” the reason that the rope breaks according to the perspective of the stationary observer (A) is:
Online Course Support | Understanding Einstein: The Special Theory of Relativity

In the twin paradox example done in lecture, how does Alice explain the fact that when she returns, Bob has aged more than she has, even though on both legs of her trip when she was traveling at 0.6c she observed his clocks to run more slowly than hers?
ByAdmin July 28, 2021July 29, 2021

10. Question 10 In the twin paradox example done in lecture, how does Alice explain the fact that when she returns, Bob has aged more than she has, even though…

Read More In the twin paradox example done in lecture, how does Alice explain the fact that when she returns, Bob has aged more than she has, even though on both legs of her trip when she was traveling at 0.6c she observed his clocks to run more slowly than hers?
Online Course Support | Understanding Einstein: The Special Theory of Relativity

In the twin paradox example done in lecture, it seems that Alice’s and Bob’s situations should be parallel or symmetric to each other. That is, Bob observes Alice travel to the star and back, but from Alice’s frame of reference, it is Bob that travels away (in the opposite direction) and returns. Why aren’t their situations symmetrical?
ByAdmin July 28, 2021July 29, 2021

7. Question 7 In the twin paradox example done in lecture, it seems that Alice’s and Bob’s situations should be parallel or symmetric to each other. That is, Bob observes…

Read More In the twin paradox example done in lecture, it seems that Alice’s and Bob’s situations should be parallel or symmetric to each other. That is, Bob observes Alice travel to the star and back, but from Alice’s frame of reference, it is Bob that travels away (in the opposite direction) and returns. Why aren’t their situations symmetrical?
Online Course Support | Understanding Einstein: The Special Theory of Relativity

On a spacetime diagram with time in years and x in light years, what is the slope of a world line of a faster-than-light object that is moving to the right (positive x direction)?
ByAdmin July 28, 2021July 29, 2021

1. Question 1 On a spacetime diagram with time in years and x in light years, what is the slope of a world line of a faster-than-light object that is…

Read More On a spacetime diagram with time in years and x in light years, what is the slope of a world line of a faster-than-light object that is moving to the right (positive x direction)?
Online Course Support | Understanding Einstein: The Special Theory of Relativity

In the “pole in the barn” example done in lecture, even though Alice’s pole is 10 meters long, and Bob’s barn is 8 meters long, Bob thinks that Alice’s pole will fit completely inside as she goes through the barn. Why does he think this?
ByAdmin July 28, 2021July 29, 2021

4. Question 4 In the “pole in the barn” example done in lecture, even though Alice’s pole is 10 meters long, and Bob’s barn is 8 meters long, Bob thinks…

Read More In the “pole in the barn” example done in lecture, even though Alice’s pole is 10 meters long, and Bob’s barn is 8 meters long, Bob thinks that Alice’s pole will fit completely inside as she goes through the barn. Why does he think this?
Online Course Support | Understanding Einstein: The Special Theory of Relativity

In the “pole in the barn” example done in lecture, how can Bob observe/photograph the front of the pole to be located at the rear door of the barn at 44.4 nanoseconds and the rear of the pole to be located at the front door of the barn at 44.4 nanoseconds (so the entire pole is in the barn), while Alice agrees with Bob’s clock readings but never herself observes the pole to be entirely within the barn?
ByAdmin July 28, 2021July 29, 2021

8. Question 8 In the “pole in the barn” example done in lecture, how can Bob observe/photograph the front of the pole to be located at the rear door of…

Read More In the “pole in the barn” example done in lecture, how can Bob observe/photograph the front of the pole to be located at the rear door of the barn at 44.4 nanoseconds and the rear of the pole to be located at the front door of the barn at 44.4 nanoseconds (so the entire pole is in the barn), while Alice agrees with Bob’s clock readings but never herself observes the pole to be entirely within the barn?
Online Course Support | Understanding Einstein: The Special Theory of Relativity

For an object that is moving to the right (positive x direction), under what circumstances can we get a reversal of cause and effect?
ByAdmin July 28, 2021July 29, 2021

6. Question 6 For an object that is moving to the right (positive x direction), under what circumstances can we get a reversal of cause and effect? 1 point …

Read More For an object that is moving to the right (positive x direction), under what circumstances can we get a reversal of cause and effect?
Online Course Support | Understanding Einstein: The Special Theory of Relativity

Consider the twin paradox example done in lecture: On Alice’s outbound trip to the star, Bob observes Alice’s clocks running slower than his clocks. What does Alice observe regarding Bob’s clocks?
ByAdmin July 28, 2021July 29, 2021

3. Question 3 Consider the twin paradox example done in lecture: On Alice’s outbound trip to the star, Bob observes Alice’s clocks running slower than his clocks. What does Alice…

Read More Consider the twin paradox example done in lecture: On Alice’s outbound trip to the star, Bob observes Alice’s clocks running slower than his clocks. What does Alice observe regarding Bob’s clocks?

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