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
During 1 second, the velocity of an object
increases by 45 meters/second.
- It is known that the velocity of the object will
eventually increase by 8 meters/second.
- If the rate remains constant, how many seconds
will be required?
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Problem Number 2
What are the magnitude and angle of a vector whose
x and y components are respectively 5 and 8.4?
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Problem Number 3
By how much does the velocity of an object of mass 3 Kg change under the following
conditions:
- The object experiences a variable net force F(t) for .03 seconds, if the force has the
following characteristics:
- The force vs. clock time graph increases linearly from 0 Newtons at the beginning of the
.03-second interval to 207 Newtons, then decreases linearly back to 0 at the end of the time
interval.
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Problem Number 4
An ideal spring has restoring force constant 430 Newtons/meter. An unknown mass
on the spring is observed to complete 58.824 cycles every minute. What is the unknown
mass, in kilograms?
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Problem Number 5
An object is moving at a constant velocity of 9 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 4 m/s
per second, and if the acceleration phase lasts 7 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 6
An object of mass 4 kg is moving to the right at 3 m/s. It collides with a second
mass of 8 kg which is moving at -7 m/s (the negative velocity indicates that the motion
is toward the left).
During the collision, which lasts
for .042 seconds, the objects exert equal and opposite forces on one another.
The first object ends up with a
velocity of -3 m/s (toward the left).
- What was the average force exerted
by the second object on the first?
- What was the average force exerted
by the first object on the second?
- 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 7
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 8
What vector of magnitude 9.19 must be added to A =
< -.39, -6.2> in order to obtain a vertical vector R? Answer by giving the magnitude
and angle of the vector to be added.
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whose x component is u and whose y component is v.)
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Problem Number 9
From the length and mass of a simple pendulum we determine that the restoring
force constant is k = m g / L. A bullet of mass 28 grams and moving at
unknown velocity is quickly absorbed into the 5.7 kg mass of the pendulum, which
is initially at rest. The pendulum absorbs the bullet, and its mass is
observed to move to a maximum displacement of .068 meters from the equilibrium
position.
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 10
If no energy is dissipated (e.g., against friction
or air resistance) when you push an object, the increase in the energy of motion (kinetic
energy, abbreviated KE) of the object is equal to the work you do on it. Since there is
always some dissipation of energy in the real world, this is an ideal case.
- If you exert a force of 260 Newtons while pushing an
object 80 meters, with no energy dissipated, what will be its increase in kinetic energy?