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Precalculus II
Technical Physics (Phy 111) Final Exam
Completely document your work and your reasoning.
You will be graded on your documentation, your reasoning, and the
correctness of your conclusions.
Test should be printed using Internet Explorer. If
printed from different browser check to be sure test items have not been cut off. If
items are cut off then print in Landscape Mode (choose File, Print, click on Properties
and check the box next to Landscape, etc.).
Name and Signature of Student
_____________________________
Signed by Attendant, with Current Date and Time:
______________________
If picture ID has been matched with student and name as
given above, Attendant please sign here: _________
Instructions:
- Test is to be taken without reference to text or
outside notes.
- Graphing Calculator is allowed, as is blank paper or
testing center paper.
- No time limit but test is to be taken in one
sitting.
- Please place completed test in Dave Smith's folder,
OR mail to Dave Smith, Science and Engineering, Va. Highlands CC, Abingdon, Va.,
24212-0828 OR email copy of document to dsmith@vhcc.edu,
OR fax to 276-739-2590. Test must be returned by individual or agency supervising test. Test is not to be returned to student after it has been taken. Student may, if proctor deems it feasible, make and retain a copy of the test..
Directions for Student:
- Completely document your work.
- Numerical answers should be correct to 3 significant
figures. You may round off given numerical information to a precision consistent
with this standard.
- Undocumented and unjustified answers may be counted
wrong, and in the case of two-choice or limited-choice answers (e.g., true-false or
yes-no) will be counted wrong. Undocumented and unjustified answers, if wrong, never get
partial credit. So show your work and explain your reasoning.
- Due to a scanner malfunction and other errors some
test items may be hard to read, incomplete or even illegible. If this is judged by
the instructor to be the case you will not be penalized for these items, but if you
complete them and if they help your grade they will be counted. Therefore it is to
your advantage to attempt to complete them, if necessary sensibly filling in any
questionable parts.
- Please write on one side of paper only, and staple
test pages together.
Test Problems:
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Problem Number 1
A space explorer observes an inhabitant with unknown intentions idly swinging a
rock back and forth at the end of a string.
- Due to atmospheric conditions and the bizzare geometrical properties of the
planet's geological and biological structures the distance to the inhabitant is unknown,
so the size of the creature is impossible to judge.
- However, the explorer notes that when it oscillates gently back and forth the
rock completes one cycle every 5.2 seconds. She realizes that this permits her to find
the length of the rope and therefore to estimate the size of the inhabitant.
- She first pulls out a bathroom scale and weighs herself, which allows her to
easily determine that the acceleration of gravity is 8 m/s^2.
- How long is the rope?
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Problem Number 2
What is the mass in kilograms of an object if, when suspended from an ideal
spring whose restoring force constant is 20 Newtons/meter, the mass oscillates at 1.587
cycles/sec.
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Problem Number 3
A mass of 3.5 kg released from rest at a distance of .6 meters below its
equilibrium point. If the object is subjected to a net restoring force with force
constant 93 N / m, then
- What is the centripetal acceleration, in m/s ^ 2, of the reference point on the
circle which models the resulting simple harmonic motion?
- What acceleration would you expect for the object at the instant it reaches an
extreme point?
- Explain in your summary why you would expect the object itself to undergo this
acceleration at the extreme positions in its cycle.
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Problem Number 4
An object of mass 15 kg experiences a net force of 19200 Newtons for .4 seconds.
- Use the Impulse-Momentum Theorem to find its change in velocity.
- Use Newton's Second Law and your knowledge of uniformly accelerated motion to obtain the
same result.
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Problem Number 5
If a displacement vector has x and y components 8.1
meters and 8 meters, respectively, the what are the magnitude and angle the
displacement?
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Problem Number 6
What vector of magnitude 9.19 must be added to the
force vector A = < -6.77 Newtons, 5.84 Newtons> in order to obtain a vertical vector
R? Answer by giving the magnitude and angle of the vector to be added.
- (Note on notation: <u,v> stands for a vector
whose x component is u and whose y component is v.)
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Problem Number 7
An object moving at 9 m/s collides with an object moving at -6 m/s. The mass of
the first object is 7 kg and the mass of the second is 7 kg.
After the collision the first
object is observed to have velocity 2 m/s.
- What will be the velocity of the
second object after the collision?
- How do the kinetic energy totals
before collision compare with those after collision?
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Problem Number 8
An ideal spring has an unknown restoring force constant. An mass of 7.478 kg
suspended from the spring is observed to complete a cycle of oscillation in .81
seconds. What is the restoring force constant?
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Problem Number 9
An object is moving at a constant velocity of 4 m/s before an acceleration phase, and
at another constant velocity after the acceleration phase.
- If during the acceleration phase the velocity changes at a rate of 7 m/s
per second, and if the acceleration phase lasts 4 seconds, then what will be the increase
in velocity?
- What will be the second constant velocity?
- What will be the average velocity?
- How far will the object travel during the acceleration phase?
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Problem Number 10
During each second, the velocity of an
object increases by 9 meters/second.
- It is known that the velocity of the object will
eventually increase by 35 meters/second.
- If the rate remains constant, how many seconds will
be required?
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Problem Number 11
An engine drives a vehicle a distance of 9 meters.
- The vehicle carries enough fuel to supply 153 Joules of energy.
- How great a constant force can theoretically be supplied by the engine
before exhausting its fuel, assuming all the fuel energy could be converted to useful work
(this is in fact impossible, as we will see later; but the calculation is important as a
reference value in calculating efficiency)?
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Problem Number 12
An object, initially at rest, is acted upon by a net force of 43.35 Newtons. The object
has mass 5.1 kilograms.
- What will be its acceleration, and what will be its speed after the first
7.5 seconds of acceleration?
- How far will it travel up to this time?