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Home Q & A Board Science-Related Homework Help Physics
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LU DEE LU DEE
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6 years ago
Which of the following descriptions shows two objects of EQUAL mass-energy?
  Two identical balls with the same speed and at the same height, except moving vertically in different directions
  A 10 kg sphere of iron at 300 K and a 12 kg sphere of iron at 10 K
  Two identical spheres of copper, except one is at 300 K and one is at 3000 K
  Two identical bullets, except one bullet is fired from a special gun at 0.5c and the other bullet is at rest.


[Ques. 2] Which of the following scenarios would NOT demonstrate the usefulness of a spacetime diagram?
 
Determining whether an event separated in space and time can affect a future event
  Telling whether clocks are synchronized
  Showing how inertial frames affect simultaneity
  Examining the twin paradox problem
  Answer not shown



[Ques. 3] A muon detector on Mount Washington observes greater numbers of muons than an identical detector located at a lower elevation, for example in Boston. The number detected in Boston, however, is much greater than the number predicted when considering the elevation separation between Boston and Mount Washington, the muons' speed, and the time of the muons' half-life. Why is this so?
 

 

The muons are traveling faster than the speed of light
  The addition of velocities increases the muons' half-life


 

The muons' speeds are large enough for relativistic effects to occur
  The detectors must be faultythe number predicted is classically correct


 



[Ques. 4] John is in an inertial frame F and Jack is in a frame F' moving relative to F in the x-direction at a constant velocity v. John and Jack each hold a 1-m stick with them oriented in the x-direction. Which one of the following statements best describes the situation?
 
A.John measures Jack's stick as shorter than his own
  B.Jack measures John's stick as shorter than his own
  C.The time it takes John to measure Jack's stick does not factor into John's calculation
  D.Both a and b
  E.All of the above



[Ques. 5] Which of the following statements about the Michelson-Morley experiment is correct?
 
A.The physics world was immediately convinced of the null result on ether.
  B.The interferometer measured large effects from the ether, showing that the velocity of light changes depending on motion with respect to the ether.
  C.Changing the angle of the interferometer produced different results.
  D.They found that the interference effects of the ether were not dependent on the direction of motion of the interferometer.



[Ques. 6] Using Maxwell's equations, the speed of light can be calculated using which of the following fundamental physical constants? Select the letter that most completely answers the question.
 
I, II, III
  III, IV
  I, II
  IV, VI
  II, V



[Ques. 7] Which of the following represents one of the major splits in physical science before and after about 1895?
 
The loss of the feeling that everything in nature could be understood through reasoning with the introduction of quantum mechanics after about 1895.
   With the explanation of blackbody radiation in 1887, after 1895 the world worked towards modeling quantum mechanics.
   The ether was found to exist and was generally accepted after about 1895 as the electromagnetic medium.
   Both matter and light appeared to be best modeled by a wave rather than a particle after about 1895.



[Ques. 8] Which of the following statements about the atomic theory of matter is true?
 
Einstein helped prove the atomic theory by explaining x-ray production in 1905.
  The atomic theory of matter was universally accepted at the end of the nineteenth century.
  Proust put forth the law of definite masses, saying that a compound is made up of numbers of atoms so that the total of each element has equal mass.
  Dalton proposed that atoms of each element have characteristic properties.
  Atoms were originally thought of as particles, but the work of Dalton and Brown helped prove that atoms were waves.



[Ques. 9] Which of the following statements shows the electromagnetic force at work?
 
A stable nucleus of 4 protons and 5 neutrons
  A rubber band stretching but not breaking
  Beta decay of 139Ba
  Collapse of a star into a black hole
  Quarks attracted to one another within a proton



[Ques. 10] Scientists have made great strides towards unifying the fundamental forces of nature. At the time of the publishing of the text, the most unified of theories shows that the total number of forces to be fundamental in physics is
  3
  1
  2
  4
  5
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#1
6 years ago
1)  The objects have the same rest mass, are moving with the same speed, and have the same amount of potential energy. The direction of travel does not affect the mass-energy.

2)  All of the answers above are true demonstrations of the usefulness of a spacetime (or Minkowski) diagram.

3)  Einstein's special theory of relativity implies that moving objects experience time dilation. The half-life of stationary muons is a known value, and the explanation for greater numbers than classically predicted lower in the atmosphere comes from using the distance covered by the muons and the stationary half-life. The correction comes from the time dilation the muons experience.

4)  A.
While John indeed measures Jack's stick as shorter than his own, this is not the statement that best describes the situation. John sees Jack's frame of reference as moving with respect to his own, and by the special theory of relativity, moving objects appear shorter to non-moving observers

5)  D. They thought that movement through the ether, which supposedly had some inherent motion itself, would create interference effects in their interferometer. Instead, they saw no effects whatsoever on the direction of the motion of the interferometer through space and the interference patterns on the interferometer.

6)  I,II
Using Maxwell's equations and both the permeability and permittivity of a vacuum, the speed of light can be calculated.

7)  At the turn of the 20th century, quantum mechanics and the uncertainties inherent to its application created the feeling that experimentation could no longer let scientists know everything about any given system. Reasoning and theory were by no means dead, but certainly scientists understood their limits.

8)  Called the father of atomic theory, Dalton's theories of molecules and different elements in proportion led the charge towards accepting the concept of the atom.

9)  Electromagnetic forces bond molecules together and keep them from separating. A rubber band stretches but does not separate due to bonding, or from a physics perspective, distribution of charges.

10)  3
at this point in time the three fundamental forces are gravity, the electroweak, and the strong force. The electromagnetic and weak forces were proven to be facets of the same force in the 1970's. GUT's strive to further unify the three forces into 2 or even just 1.
LU D. Author
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#2
6 years ago
Such an awesome helper!
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