Time and Date Stamps (logged): 17:12:20 06-10-2020
°¶Ÿ°±Ÿ±¯¯µŸ°¯Ÿ±¯±¯
Precalculus II
Principles of Physics (Phy 121) 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:
. . . . .
. . . .
. . . .
. . .
.
.
.
.
.
.
.
.
.
.
Problem Number 1
You walk along level ground in a straight line from
some initial point to some terminal point.
If I walk 4.17 miles to the East, then 2.36 miles to
the North, I will have walked 6.53 miles, and will end up at the same point you do.
- What angle does your path make with East?
- How far did you walk?
.
.
.
.
.
.
.
.
.
.
Problem Number 2
In order to stop a moving object, the object must be caused to expend a total of 108
Joules of energy.
- This is caused by exerting a force on the moving object, which must then
exert an equal and opposite opposing force and must hence do work.
- How much force must be exerted against the object if it is to be stopped
within a distance of 6 meters?
.
.
.
.
.
.
.
.
.
.
Problem Number 3
An object of mass 12 Kg is acted upon by an unknown force F for `dt = 6 seconds. Its
velocity is observed to change during this time from 5 m/s to -79 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.
.
.
.
.
.
.
.
.
.
.
Problem Number 4
An object of mass 6 kilograms is acted upon by a net force of 22 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?
.
.
.
.
.
.
.
.
.
.
Problem Number 5
An object of mass 10 kg experiences a net force of 1770 Newtons for .07 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.
.
.
.
.
.
.
.
.
.
.
Problem Number 6
What are x and y the components of the force vector
obtained when we add the two following force vectors:
- vector A, with x and y components 9.2 and
-6.9 , and
- vector B whose x and y components are 5 and
-6.9 ?
What are the magnitude and angle of the resultant
vector?
.
.
.
.
.
.
.
.
.
.
Problem Number 7
A displacement vector has length 9 and is
directed at an angle with the positive x axis of 87 degrees. What are the
displacements in the x and y direction which would give the same net displacement?
.
.
.
.
.
.
.
.
.
.
Problem Number 8
If an object of mass 6.5 Kg is pushed by a net force of 32.5 Newtons for 4.3 seconds, how
far does it travel and what is its final velocity, assuming that no energy is dissipated?
How much work is done?
.
.
.
.
.
.
.
.
.
.
Problem Number 9
An object of mass 7 kg is moving to the right at 5 m/s. It collides with a second
mass of 5 kg which is moving at -8 m/s (the negative velocity indicates that the motion
is toward the left).
During the collision, which lasts
for .086 seconds, the objects exert equal and opposite forces on one another.
The first object ends up with a
velocity of -4 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?