PHYS146 Exam 1 Information

1. Why is a static (non-expanding, non-contracting) universe impossible in a Universe governed by Newton's Law of Gravity?

2. It has been argued that the Universe could not have a beginning of time because of the paradoxical question of what would there have been before the Universe began. Criticize this argument.

3. What is the nature of a scientific theory? In other words, what does a scientific theory or law do?

4. Can you prove a theory to be true? False?

5. What would characterize a good scientific theory?

6. What is the crucial experimental result that leads logically to Einstein's Theory of Relativity?

7. What are the three strange phenomena predicted by Special Relativity?

8. Do all observers agree on the time at which events occur?

9. Do all observers agree on whether two events are simultaneous?

10. What happens to a rod moving close to the speed of light? What would its length be when it was moving at a speed just short of the speed of light? If an observer was moving with the meter stick, what length would he measure for the meter stick? What would he find for the length of a stationary meter stick?

11. What happens to a clock moving close to the speed of light? What would its rate be if it was moving at a speed just short of the speed of light? If an observer was moving with the clock, what would he find for the rate of the moving clock? What would he find for the rate of a stationary clock?

12. Draw a graph showing qualitatively what the length of a meter stick would be if it was moving a various speeds from 0 to the speed of light.

13. Draw a graph showing qualitatively what the time between ticks of a clock would be when it was moving a various speeds from 0 to the speed of light. Assume that the ticks are 1 second apart when the clock is not moving.

14. Why are the effects of Special Relativity not obvious in everyday life?

15. What is the fastest speed possible for any object? What enforces the limit?

16. Can a particle have a negative mass? What would be the observable effects of a particle having a negative mass?

17. What are antiparticles and why do they exist?

18. It is sometimes said that the Theory of Relativity shows that everything is relative and that there are no absolutes. Please comment.

19. Can scientific theories be determined to be true by pure thought? If so, how; if not, why not?

20. Given the existance of the nuclei in a table, how would you explain the given values of mass and charge? [Assignment 1]

21. There is no direct way for us to know whether the universe is finite. Why not?

22. In Chemistry it is known that after a reaction, the masses of the products sum to a number not measurably different from the sum of the masses of the reagents [the atoms you have before the reaction]. Is this statement true for Elementary Particles? If there is less mass after the reaction, what if anything happens to the missing mass. If there is more mass after the reaction, where did it come from?

23. Why is it simpler to say that the relativistic transformation laws are a property of space and time itself rather than of the objects which are moving?

24. Is there such a thing as a Newtonian transformation law or did Einstein invent the concept of a transformation law as well as the form of the law at high velocity?

25. Why do we not know for sure the present form of galaxies which are several billion light years away? How do we figure out what their form should be?