RELATIVITY (Physics 2)
1. You are inside a spaceship that is a mile long. An alien spaceship flies past you. When the passing alien is alongside you, you note that the alien ship is exactly as long as your own ship. In other words, the alien nose is abreast of your tail when the alien tail is abreast of you nose – according to your time. Are the two ships identical in rest length? Explain.
2. From question 1, you measured the passing alien ship to be exactly as long as your ship. How would the alien view the length of your ship compared to its own ship? Explain.
3. A square box is being lowered very rapidly onto a very rapidly moving conveyor belt, as illustrated below.
How will the box look to people riding the belt? (Assume the box falls to the side of the people, not right at them – the conveyor belt is very wide.)
a. b. c. d. e.
Explain.
4. How fast does a clock have to travel in order that its hands move at half speed?
5. Back to the clock -- how would its 'moving' density compare to its 'rest' density? Analyze numerically.
(Hint: Assume the clock is a uniform cube)
6. A rubber stamp instantly stamps the letter 'H' on a moving sheet of paper.
a. Describe how the 'H' on the paper would look to you.
b. Describe how the 'H' on the paper would look to someone riding on the paper.
c. Describe how the 'H' on the stamp would look to someone riding on the paper.
d. Is there a discrepancy between your answers to b. and c.? If so, can you make sense of it? Explain.