Time and Date Stamps (logged): 05:17:06 12-05-2008
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Precalculus II
General College Physics (Phy 201) Test 1
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
An Atwood machine consists of masses of 1 Kg and
1.06 Kg hanging from opposite sides of a pulley.
- As the system accelerates 2.3 meters from rest, how
much work is done by gravity on the system?
- Assuming no friction or other dissipative forces,
use the definition of KE to determine the velocity of the system after having moved
through the 2.3 meters, assuming that the system was released from rest.
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Problem Number 2
Sketch and label force diagrams for each of the following situations:
A mass of 35 grams is attached to a cart of mass 280 grams and suspended over a pulley
of negligible mass and friction. The cart is placed on a ramp whose slope is just enough
to compensate for the small frictional force acting on the cart. When the system is
released, what will be the acceleration of the cart?
Answer the same question if the cart is placed on a ramp making an angle of 3 degrees
with horizontal, with the cart being pulled down the ramp, and if the frictional force is
.026 times the normal force on the cart.
If the ramp is tilted in the reverse direction, at what ramp angle will the cart
experience an acceleration of the same magnitude but in the opposite direction?
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Problem Number 3
A ball of mass 8 kg rolls off the edge of a ramp with a horizontal speed of 70 cm/s.
- What is its KE as it rolls off the ramp?
How much work does gravity do on the ball as it falls 14 cm?
What will be its kinetic energy after falling 14 cm?
How much of this KE is accounted for by its horizontal velocity, and how much by its
vertical velocity?
What then is its vertical velocity at this point?
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Problem Number 4
A cart of mass 1.5 kg coasts 30 cm down an incline at 4 degrees with horizontal.
Assume that the frictional force is .026 times the normal force, and that other
nongravitational forces parallel to the incline are negligible.
- What is the component of the cart's weight parallel to the incline?
- How much work does this force do as the cart rolls down the incline?
- How much work does the net force do as the cart rolls down the incline?
- Using the definition of kinetic energy determine the velocity of the cart after
coasting the 30 cm, assuming its initial velocity to be zero.
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Problem Number 5
A ball reaches a ramp of length
34 cm with an unknown initial velocity and accelerates uniformly along the ramp, reaching
the other end in 3 seconds. Its velocity at the end of the ramp is determined to be 4.666666
cm/s. What is its acceleration on the ramp?
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Problem Number 6
An object is given an unknown initial velocity up a ramp on which its
acceleration is known to have magnitude 6 cm/s^2. It reaches a maximum distance of
40.33 cm up the ramp before rolling back down.
- What is its initial velocity?
- How many seconds after the initial impetus does the object pass a point 5.8 cm up
the ramp from its initial position (give all possible answers)?
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Problem Number 7
Explain why the slope of a position vs. time graph between two clock times is equal to
the average acceleration between those two times.