This assignment is all about Relativity: Once you read Relativity- W. Thomas Griffith.pdf from module UNIT 13, at the end of the file you will find questions (page 454) and exercises (page 455). 2. Answer every other odd question and solve every other odd problem of document ending Exercises.

questions * : more open-ended questions, requiring lengthier responses, suitable for group discussion Q = sample responses are available in appendix D Q = sample responses are available on the website Q1. Q2. Q3. Q4. Q5. 06. Q7. *Q8. Q9. *Qlo. Q11. Q12. If a boat is moving downstream, will the velocity of the boat relative to the water be greater than the velocity of the boat relative to the stream bank? Explain. If a boat is moving upstream. will the velocity of the boat relative to the bank of the stream be greater than the ve- locity of the boat relative to the water? Explain. If an airplane is ying in the same direction as the wind, will the velocity of the plane relative to the ground be greater than, less than, or equal to the velocity of the plane relative to the air? Explain. Is it possible that a person in a rowboat will not be able to move upstream? Explain. If a boat is moving across a stream, will the speed of the boat relative to the bank equal the numerical sum of speed of the boat relative to the water and the speed of the water relative to the bank? Explain. If an airplane is ying in a crosswind blowing at an angle of 90 to the direction the airplane is pointed. will the speed of the plane relative to the ground be less than the speed of the plane relative to the air? Does the addition of the velocities of things like airplanes and wind speed require use of the special theory of rela- tivity? Explain. Would it be appropriate, from the perspective of special relativity, to add the velocity of light relative to the Earth to the velocity of the Earth relative to the sun to obtain the velocity of light relative to the sun? Explain. Was the ether (the assumed medium for light waves) pre sumed to exist in a vacuum? Explain. What was the MichelsonMorley experiment designed to detect? Why did they expect that the speed of light might vary at different times of the year? Explain. Did the MichelsonMorley experiment succeed in measur- ing the velocity of the ether relative to the Earth? Explain. Do either of Einstein's postulates contradict the classical assumptions of how relative velocities add? Explain. Q13. Q14. (:15. Q16. Q17. *le. *Q19. Q20, Q21. Q22. Q23. *Q24. Q25. Which of Einstein's postulates deals most directly with the failure to detect motion of the Earth relative to the ether? Explain. Is it possible that two different observers will not agree on the time taken for a light beam to bounce off a mirror and return to its source? Explain. A chess game taking place on Earth is seen by observer A, who is passing by in a spaceship. Observer B is stand ing on Earth looking over the shoulder of the players. Which of these two observers measures the longer time for the interval between moves in the game? Explain. A radioactive isotope with a certain half-life is moving with a high speed in a particle accelerator. Does an ob- server at rest in the lab measure the proper time for the half-life of this isotope? Explain. A spaceship is moving with a large velocity past observer A, who is standing on Earth. Observer B is aboard the spaceship. Which of these observers measures the longer length for the length of the spaceship? Explain. Is it theoretically possible for a father to be younger (to have aged less) than his son or daughter? Explain. Is it possible for an astronaut to leave on a space trip and to return a year before her twin sister was born? Explain. Is Newton's second law, written in the form F"cl : ma, Valid for objects traveling at velocities near the Velocity of light? Explain. Could we use the relativistic momentum expression p : ymv, for objects moving at small velocities? Explain. If we compress a spring and lock it into its newly com- pressed conguration, have we changed the mass of the spring? Explain. Is the increase in kinetic energy of an object equal to the work done to accelerate the object for an object moving at a very high speed? Explain. Is it completely correct to say that mass is converted into energy in a nuclear reaction such as a ssion reaction? Explain. If the velocity of an object is reduced to zero. does all of its energy disappear? Explain. Q26. 027. Q28. If an elevator is accelerating downward, will your apparent weight (as measured by a bathroom scale) be greater than your weight measured when the elevator is not accelerat- ing? Explain. When you are inside a closed space vehicle, is it possible for you to tell whether the vehicle is accelerating or whether you are simply near some massive body such as the sun or the Earth? Explain. Would your experiences inside a freely falling elevator be similar in any way to those inside a spaceship moving with exercises Q29. 030. 031. constant velocity when it is a long distance away from any planet or star? Explain. Does light traveling in empty space always travel in a straight line? Explain. Would a clock located on the surface of the sun measure time at the same rate as a clock located a long distance away from any planet or star? Explain. Is a black hole just a hole in space that contains no mass? Explain. E1. E2. E3. E4. E5. E6. E7. A boat that can travel with a velocity of 12 m/s in still water is moving at maximum speed against the current of a stream that ows with a velocity of 5 m/s relative to the Earth. What is the velocity of the boat relative to the bank of the stream? A plane that can travel at 460 MPH in still air is ying with a tailwind of 40 MPH. How long does it take for the plane to travel a distance of 750 miles (relative to the Earth)? A swimmer swims upstream with a Velocity of 4 m/s rela- tive to the water. The velocity of the current is 3.5 m/s (downstream). What is the velocity of the swimmer relative to the bank? A ball is thrown with a velocity of 60 MPH down the aisle (toward the tail of the plane) of a jetliner traveling with a velocity of 300 MPH relative to the Earth What is the velocity of the ball relative to the Earth? An astronaut aims a ashlight toward the tail of his space- ship, which is traveling with a velocity of 0.5a relative to the Earth. What is the velocity of the light beam relative to the Earth? The factor 'y = 1/ V1 (vi/c?) appears in many expres- sions derived from the theory of special relativity. Show that y = 1125 when v = 0.60. An astronaut cooks a threeeminute egg in his spaceship whizzing past Earth at a speed of 0.66. How long has the egg cooked as measured by an observer on Earth? (See table 20.1 .) E8. E9. E10. E11. E12. An observer on Earth notes that an astronaut on a spaceship puts in a 4hour shift at the controls of the spaceship. How long is this shift as measured by the astronaut himself, if the spaceship is moving with a velocity of 0.8: relative to the Earth? (See table 20.1. Be carefulwhich observer measures the proper time?) A spaceship that is 50 m long as measured by its occupants is traveling at a speed of 0.1: relative to the Earth. How long is the spaceship as measured by mission control in Houston? (See table 201.) The crew of a spaceship traveling with a velocity of 0.6c relative to the Earth measures the distance between two cities on earth (in a direction parallel to their motion) as 600 km. What is the distance between these two cities as measured by people on Earth'.7 (See table 20.1which observer measures the rest length?) A spaceship is traveling with a velocity of 080 relative to the Earth. What is the momentum of the spaceship if its mass is 5000 kg? (p = ymv and c = 3 X 108 m/s. See table 201.) Suppose that an object has a mass-energy of 200 joules when it is at rest. a. What is its total energy when it is moving with a veloc- ity of0.9c? (E = yEo. See table 201.) b. What is the kinetic energy of the particle at this speed? (KE = E ED)