PAST EXAMS
 
 

Your Name___________________________________________ID_______

FIRST HOURLY EXAM
FRIDAY, 16 OCTOBER 1998
 

Grade_______________________________
 

There are six questions in this closed book exam.  Write all your answers carefully, concisely, and legibly in the spaces provided on these exam sheets (drawing figures may be very helpful). If you need more writing room, use the reverse sides of the pages.  Anything that I can't read easily will not be graded.

1. Matching (20 points). Choose the item on the right that, on the basis of course readings and class discussions, best associates with the description on the left.

___a). Experimental proof that the earth's speed                                   1. Hans Christian Orsted
  through the ether could not be measured.
___b). Path of keys as seen by a trackside observer                             2. Maxwell's Equations should be valid for
  when person passing by, on constant speed                                                  all observers.
          railroad flatcar, drops set of keys.
___c). Left plenty of time to do creative physics.                                3. Simultaneity at distant events is not the same
                                                                                                                           for all observers.
___d). Work done when you throw a ball.                                         4. Michael Faraday

___e). A person listening to two loudspeakers                                      5. Principle of Equivalence
  finds a spot where he hears no sound at all.
___f). A theoretical reason for believing that the                                     6. Michelson-Morley Experiment
  velocity of light should be the same for all.
___g). Light is...                                                                                 7. Conversion of Nuclear into Heat Energy

___h). Showed  that an electric current will                                    8. Conversion of chemical energy to mechanical    produce a magnetic field.                                                                                   energy
___i). Showed that a changing magnetic field                                 9. Newton's First Law
  will produce an electric field.
___j). Cannot distinguish between an accelerated                         10. Transverse electromagnetic waves
   coordinate system and a constant
  gravitational field.                                                                          11. Parabolic orbit
                                                                                                       12. Swiss Patent Office employment

   13. Destructive interference
   14. Straight line path
   15. Constructive interference.

2 (15 points). What are the differences , advantages, and disadvantages of Einstein's approach to the representation of the gravitational interaction between bodies as compared to the approach of Newton? (Start your answer by describing each approach.)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

3 (20 points). Two hockey players, speeding across frictionless ice, collide face on with each other and then cling together. The man, whose mass is 75 kg, is initially moving forward with a speed of 5 m/s. The woman, of mass 50 kg, has a forward speed before the collision of 2 m/s.  What speed does the  pair have immediately after the collision?   How much kinetic energy is lost as a result of the collision?  What happens to this lost energy? Does this loss mean that energy is not conserved in this case? Explain your answers!
 
 
 
 
 
 

4 (15 points). Mary is waiting on the platform outside the carousel on which her cousin Bob is riding.  The carousel is turning with a constant angular speed. Bob,  in full view of Mary, drops his key - which falls to the floor of the carousel .  Describe and draw the motion of the key as seen by Bob and as seen by Mary. Explain your answers!
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

5 (15 points). Consider two electrically charged bodies near each other in space but isolated from everything else.  Compare and contrast a Newtonian description of the electrical forces between them with a Faraday field type description. What are the advantages and disadvantages of the two descriptions?  How do things change if one of the bodies is moving with respect to the other? Explain your answers!
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

6 (15 points). The Star Ship Enterprise was designed and constructed to be 100 meters long, 10 meters high, and 20 meters wide. It's captain, Jane, reports that she walks from front to back of her ship in 15 minutes while it is flying past the earth with a speed (in its long direction) of 0.95c. She also reports that when she weighed herself before breakfast, on the ship, her mass was 60 kg. Her friend Bob receives this report on Earth. From the information given, on what matters, pertaining to the description of the ship and its captain, do Bob and Jane disagree?  By how much do they disagree? On what matters do they agree? What are the values of these agreed upon quantities? Explain your answers!
 
 

Your Name___________________________________________ID_______

FIRST HOURLY EXAM
FRIDAY, 10 OCTOBER 1997
 

Grade_______________________________
 

There are six questions in this closed book exam.  Write all your answers carefully, concisely, and legibly in the spaces provided on these exam sheets (drawing figures may be very helpful).  Anything that I can't read easily will not be graded.

1. Matching (20 points). Choose the item on the right that, on the basis of course readings and class discussions, best associates with the description on the left.

___a). Measured the velocity of light in a                                         1. Newton's First Law
  long vacuum pipe.
___b). Superposition of constant horizontal                                     2. Maxwell waves
  velocity and constant vertical acceleration.
___c). Showed that the speed of light did not                                 3. Simultaneity at distant events is not the same
  depend upon the speed of the observer.                                                     for all observers.
___d). What happens to the work you do                                         4. Michael Faraday
  when you compress a spring.
___e). What happens when a bullet is fired                                      5.Chemical Energy
  from a gun.
___f). Kinetic energy of randomly moving                                     6. Michelson-Morley Experiment
  molecules.
___g). Transversely oscillating electric and                                     7. Heat Energy
  magnetic fields.
___h). A train's length is not the same for                                     8. Conversion of chemical energy to kinetic energy
  all observers.
___i). Lines of force contract parallel to their                                 9. Albert A. Michelson
  lengths.
___j). An object dropped from the mast top                                 10. Longitudinal sound waves
   of a steadily moving sailboat lands at
  the foot of the mast.                                                                      11. Parabolic orbit
                                                                                                       12. Swiss Patent Office employment
                                                                                                       13. Constructive interference
                                                                                                       14. A cannon recoils when it fires a shell
                                                                                                       15. Elastic potential energy.

2 (15 points). What are the differences , advantages, and disadvantages of Faraday's approach to the representation of electrical forces between bodies as compared to the approach of Newton?
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

3 (20 points). An American rocket, of mass 5000kg, moving with a velocity of 10m/s, bumps into and connects with a stationary Russian satellite, of mass 15000kg.  The two, now stuck together, move on together. With what speed do they now move?  How much momentum has been transferred from the rocket to the satellite?  Is the impact elastic or inelastic?  Why?
 
 
 
 
 
 

4 (15 points). Mary is waiting on the platform of the train station for the arrival of her cousin Bob.  As the train pulls in to the station, Bob, standing in the aisle of the train, in full view of Mary through the train window, drops his key - which falls to the floor of the train.  Describe and draw the motion of the key as seen by Bob and as seen by Mary.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

5 (15 points). Consider two massive bodies near each other in space but isolated from everything else.  Compare and contrast a Newtonian description of the gravitational attraction between them with a General Relativity type description.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

6 (15 points). A 10 foot long spear is thrown through the rear window of an 8 foot wide house.  The person in the house sees the rear of the spear clear the rear window before the point passes out of the opposite front window.  Explain how this is possible.  What can you say about the spear's speed?  What can you say about the spear's appearance to the person in the house?
 
 
 

Your Name___________________________________________ID_______

TAKE HOME FINAL EXAM
DISTRIBUTED MONDAY, 1 DECEMBER 1997
COLLECTED MONDAY, 8 DECEMBER
 

Grade_______________________________

There are seven questions in this exam, each worth 10 points;  the in-class final will be worth 30 points.   Write all your answers carefully, completely, concisely, and legibly  on your own sheets of paper (or a blue book). (Drawing figures may be very helpful as will numbering your pages and stapling them together in the correct order.)  Anything that I can't read easily will not be graded.

1. Discuss (confirm/deny/explain -with evidence!) the statement "reality is non-local but phenomena are local".

2 (a) Compare the force and the energy required to drive a car at a constant 30 mi/hr in a straight line with that required to drive it around a curve at the same speed. (b) Explain why more work must be done to accelerate the car from 60 mph to 70 mph than to accelerate it from 0 mph to 10 mph. (c) Consider an isolated can of compressed gas. Why does the gas rush out when the can is suddenly opened and why does the can feel cooler? (d) Compare the work required for an "interplanetary explorer"  to "escape" from a planet with that required to be "captured" by that planet. What does the work and what is the source of the required energy?

3 (a) What is "action at a distance" and why were Newton's contemporaries suspicious of it?
(b) What are the similarities, what are the differences between the gravitational force, the electrical force, and the magnetic force? (c) How does the concept of "field" deal with the problem of "action at a distance"? (d) Consider two massive bodies near each other in space but isolated from everything else.  Compare and contrast a Newtonian description of the gravitational attraction between them with a General Relativity type description.

4 (a) Contrast "pragmatism" and "realism" and name some prominent physicist supporters of each  (b) What is meant by a "covarient physical law" and why is it important? (c) How does "quantum wholeness" differ  from Newton's world view? (d) What did Einstein mean by the "incompleteness" of quantum theory?

5 Mu-mesons are "born" high above the earth's atmosphere and race towards the earth's surface with a speed of 0.8c. Their life time, according to an  observer  traveling with them, is
2 x 10-6 seconds. (a) What would be their life time according to an earth-bound observer?  How  far would this observer see the mu-mesons travel during their lifetime?  (b) If you were traveling with the mu-mesons, how far would you see them travel during their life time? (c) What quantity, relative to the mu-mesons motion during its life time, would both observers agree upon, and what is its numerical value?

6 (a) Explain the relation between "quantum tunneling" and Feynman diagrams.  (b) What is the difference between the way bosons and the way fermions appear in Feynman diagrams.  Explain the difference.

7. (a) What was "right" about Bohr's model of the hydrogen atom?  (b) What was wrong about it and how was it "fixed" by DeBroglie's hypothesis?