Old P1112 Exam 1.pdf - Section YOUR NAME Section...

Section #: ________ YOUR NAME: ___________________________
Section Instructor’s Name: ___________________________
Physics 1112 Prelim 1 Exam February 21, 2019
7:30-9:00 p.m.

PLEASE CHECK THAT THIS PACKAGE HAS 14 PROBLEMS ON 16 PAGES!
A formula and value sheet attached to a blank page to be used as scratch paper
has been handed out separately.
Write your answers directly on the question sheets in the spaces provided.
Multiple-choice problems will be graded based on the answer only; work need
not be shown.
For the other problems, show enough of your work to indicate how you arrived
at your result. Clearly label your work and your answers. For numerical
answers, be sure to give the appropriate units. If you need more space for
calculations, use the backs of the question sheets and clearly label the
whereabouts of your work for each problem. Work on separate scratch paper
will not be graded.
Advice: Do not spend too much time on any one problem or part of a problem.
Solve the problems that you can solve easily first, and then return to the more
difficult problems. It’s a good use of your time to read the entire exam before
starting.
This is a closed book exam. You may use non-graphing calculators.

For grading use only:
1-2. _____________ / 6 9. _____________ / 12 14. _____________ / 20
3. _____________ / 6 10. _____________ / 7
4. _____________ / 6 11. _____________ / 15
5-7. _____________ / 7 12. _____________ / 10
8. _____________ / 6 13. _____________ / 5
Total: _____________ / 100

Your Name: __________________________________
1
Multiple Choice. For each of the following multiple choice questions, please
write the letter(s) corresponding to the best correct answer(s) in the box
provided.
1. [3 points] The speed
v
of deep-water ocean waves depends on g , the
magnitude of acceleration due to gravity, and λ , the wavelength of the
waves. Use dimensional analysis (consistency of units) to determine the
dependence of
v
on g and λ . “
∝
” means “proportional to”.
A .
v g λ ∝
. B .
v g λ ∝
.
C .
1 2
v g λ ∝ .
D . v g λ ∝ . E . v g λ ∝ .
2. [3 points] Consider the vector A

and coordinate system
shown in the figure to the right. Which of the following
is/are correct? Give all that apply.
A .
| | 0 < A

. B .
| | 0 > A

.
C .
0
x
A <
and
0
y
A <
. D .
0
x
A >
and
0
y
A >
.
E .
0
x
A <
and
0
y
A >
. F .
0
x
A >
and
0
y
A <
.
G . None.
A
 x +
y +

Your Name: __________________________________
2
3. [6 points] Four identical blocks,
numbered 1-4, on a horizontal
frictionless surface, are pushed against a
vertical wall by a horizontal force F

exerted on Block 1 (see figure to the
right).
(a) (3 points) In which 3
rd
law interaction pair of block-to-block or block-
to-wall contact forces do the forces have the largest magnitude?
A . 1 ↔ 2. B . 2 ↔ 3. C . 3 ↔ 4. D . 4 ↔ Wall.
E . All the same.
Now the wall is removed so that the
blocks can slide freely across the
frictionless surface.
(b) (3 points) In which 3
rd
law interaction pair of block-to-block contact
forces do the forces have the largest magnitude?