Time and Date Stamps (logged): 12:44:20 05-21-2012
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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
You walk along level ground in a straight line from
some initial point to some terminal point.
If I walk 3.13 miles to the North, then I will be
directly West of your terminal point. Your terminal point will lie 3.77 miles to the
East.
- What angle does your path make with East?
- How far did you walk?
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Problem Number 2
A mass of 7.3 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 43 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 3
The velocity of an object increases at a
constant rate of 10 meters/second per second.
- How long will it therefore take the object to
increase its velocity by 4 meters/second?
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Problem Number 4
A bullet of mass 43 grams and moving at unknown velocity is quickly
absorbed into the 9.1 kg mass of a ballistic pendulum, initially at rest, which
quickly and completely absorbs the bullet. The mass of the pendulum is observed to
move to a maximum displacement of .081 meters from the equilibrium position.
From the length and mass of the pendulum we determine that the restoring force constant is
k = m g / L.
- Find the velocity of the mass immediately after absorbing the bullet, and the
velocity of the bullet immediately before impact. Assume that no dissipative forces act on
the system after the collision.
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Problem Number 5
The velocity of an observed object increases at a rate of 7 m/s per second. The object
is observed for 6 seconds.
- By how many meters/second does the velocity increase during this time?
- If the velocity at the beginning of the observation is 9 meters/second,
then what is the velocity at the end of the observation?
- What is the average velocity during the observation?
- How far does the object move during observation?
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Problem Number 6
Two objects collide and remain stuck together after
collision.
One object has mass 7 kg and is moving in the
positive direction at 15 m/s and the other has mass 7 kg and and moves at 27 m/s in the
negative direction.
- What is their total momentum, and what will be the
velocity of this system immediately after collision?
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Problem Number 7
An object originally moving at a constant speed is acted upon for a specified time by a
constant force of 90 Newtons.
- At the end of the specified time the force is removed and the object
proceeds at a new constant velocity.
- If the object traveled a distance of 120 meters while under the influence
of the force, and if 7128 Joules of kinetic energy are dissipated to friction, then by how
much will the kinetic energy of the object increase>
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Problem Number 8
What are the magnitude and angle of a vector whose
x and y components are respectively 8.8 and 3.4?
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Problem Number 9
An object of mass 6 Kg is acted upon by an unknown force F for `dt = .08 seconds. Its
velocity is observed to change during this time from 7 m/s to 1.64 m/s.
- Use the Impulse-Momentum Theorem
to determine the average force exerted on the object.
- Verify your results using your
knowledge of uniformly accelerated motion.
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Problem Number 10
An object of mass 7 kilograms is acted upon by a net force of 34 Newtons.
The object is initially at rest.
- What will be the acceleration of the object?
- What will be its velocity 4 seconds after it starts?
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Problem Number 11
Given that for small displacements from equilibrium the restoring force on a
simple pendulum is in the same proportion to its weight as its displacement from
equilibrium is to its length, and given a simple pendulum of length 1.35 meters and
mass .7 kilograms:
- What is the restoring force constant, analogous to the spring constant of a
spring, for this pendulum, based on the restoring force corresponding to .1 of its length?
- What should be the period of its motion?
Choose any mass and recalculate your result. Compare with your previous
result and explain why the results should compare as they do.
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Problem Number 12
What is the mass in kilograms of an object which oscillates at .9523 cycles /
sec when suspended from an ideal spring whose restoring force constant is 840
Newtons/meter?