Physics 131-1 Test 3
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Questions (8 pts. apiece) Answer in complete, well-written sentences WITHIN the spaces provided.
- If someone told you that the area of a circle was
, how could you refute them immediately?
- Recall the laboratory entitled Conservation of Angular Momentum where you dropped a
weight onto a rotating disk. The addition of the weight changes the moment of inertia
of the system. What information do you need to measure to account for the change?
Clearly describe each part of your answer.
- Assume that an object is moving in a circle of constant radius,
.
Using the general relationship between a length of arc,
, on a circle and
the variables
and
in radians
take the derivative of
with respect to time to find the velocity of the object.
Show how the magnitude
of the linear velocity,
, is related to the magnitude of the angular velocity,
.
- Recall the laboratory entitled Periodic Motion where you studied the motion
of a weight oscillating on a spring.
When the mass has its maximum positive velocity, is its distance from the detector maximum, minimum, the
equilibrium value, or some other value?
Explain your answer using Newton's Laws and/or conservation of mechanical energy.
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- For many years it was considered impossible by many to use rockets in space because the
exhaust (i.e. the burnt fuel) propelled from the rocket had nothing to push against.
On Jan. 13, 1920 the editorial page of the New York Times made the following statement about
a proposal by Robert Goddard (now recognized as the father of American rocket science).
Was the Times' correct and how might you respond?
Problems. Clearly show all reasoning for full credit.
Use a separate sheet to show your work.
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Physics 131-1 Exam Sheet, Test 3
Speed of Light ( ) |
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proton/neutron mass |
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 |
 |
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Gravitation constant |
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Earth's radius |
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Earth-Moon distance |
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Electron mass |
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