Exercise 4.1
Check your answers against those in the ANSWER section.
Listed below are the selling prices (in thousands of dollars) of a
sample of 20 vehicles sold by salespeople employed by Ray
Steele Auto Group in Albuquerque, New Mexico.
a.
Sort the data from low to high.
b.
Draw a dot plot for the data.
26
21
18
22
29
28
28
25
28
24
30
22
35
35
25
35
25
20
37
26

Exercise 4.2
Check your answers against those in the ANSWER section.
The Jansen Motor Company has developed a new engine to
further reduce gasoline consumption. The new engine was put in
20 mid-sized cars and the number of miles per gallon recorded
(to the nearest mile per gallon).
Use the Jansen Motor Company data to construct a stem-and-
leaf chart.
29
32
20
30
39
27
28
21
36
20
27
18
32
37
29
30
23
25
19
30
Exercise 4.3

Check your answers against those in the ANSWER section.
Listed to the right are the selling prices (in thousands of
dollars) for a sample of 19 lakeside lots in Pinnacle Peak, a
vacation home community in the Blue Ridge mountains.
Determine the following:
a.
the first quartile
b.
the third quartile
c.
the median
d.
Draw a box plot for the data.
86
61
148
81
39
142
140
65
28
85
90
92

25
50
85
85
82
120
137
Exercise 4.4
Check your answers against those in the ANSWER section.
An automobile dealership pays its salespeople a salary plus a
commission on sales. The mean biweekly commission is $1385,
the median $1330, and the standard deviation $75.
a.
Is the distribution of commissions positively skewed, negatively
skewed, or symmetrical?
b.
Compute the coefficient of skewness to verify your answer.
Exercise 4.5
Check your answers against those in the ANSWER section.
The fuel tank capacity in gallons and the cruising range is given
for 6 SUV’s.
a.

Develop a scatter diagram for the data.
b.
How would you characterize the relationship between fuel tank
capacity and cruising range?
Capacity in gallons
Cruising range in miles
22
445
21
405
23
410
24
420

24
365
25
380
Work Gender
place
Male
female
Total
Home
8
14
22
office
12
6
18
Total
20
20
40
Exercise 4.6
Check your answers against those in the ANSWER section.

Use the contingency table in Problem 7 to answer the following:
a. What percent of the males work at home?
b. What percent of the males work at the office?
c. What percent of the employees work at the office?
Phy 2201 page - 1 -
Physics
2201
Homework
III
part
2.
Fall
2015.
Due:
Tuesday
November
17,
2015

Show
all
work
with
clear
setup
and/or
explain
all
answers.
All
solutions
must
be
based
on
work
and/or
energy
methods.
10
points
each.
Partial
credit
is
available.
1)
A
1.4
kg

falling
object
(subject
to
the
effects
of
aerodynamic
drag)
is
1800
m
high,
traveling
at
34
m/s
and
has
not
yet
reached
terminal
speed.
It
first
reaches
terminal
speed
at
a
height
of
1340

m
and
the
terminal
speed
is
37.3
m/s.
a)
Determine
if
the
mechanical
energy
(
�
E = K + Ug)
of
the
system
consisting
of
the
falling
object
and
Earth’s
gravity
field
has
been

conserved
during
the
fall
from
1800
m
to
500
m.
b)
How
much
work
(if
any)
including
the
correct
sign
(+
or
-­‐)
has
been
done
on
the
system
over
this

interval
(presumably
by
the
external
drag
force)?
c)
Will
the
energy
of
the
system
consisting
of
the
object,
the
gravity
field
and
the
surrounding
air
be
conserved
over
this
interval?
Explain
your
answer.
Is

there
an
additional
energy
that
must
be
accounted
for
in
this
analysis?
What
is
it
and
how
much
of
it
has
been
generated?
Note:
terminal
speed
is
a
constant
speed.

2)
The
0.2
kg
box
below
slides
down
a
curved
ramp,
jumps
a
small
gap
and
lands
on
a
flat
platform.
At
the
point
on
the
ramp
shown
it
is
1.5
m
above
the
floor

and
its
speed
is
2.0
m/s.
At
the
point
shown
on
the
platform
the
box
is
0.4
m
above
the
floor
and
sliding
at
4.2
m/s.
a)
If
we
consider
a
system

consisting
of
the
box
and
Earth’s
gravity
field
so
that
�
E = K + Ug ,
has
the
energy
of
this
system
been
conserved
during
the
described
process?
Explain
how
you
know.
b)
If
we

consider
the
exact
same
process
but
broaden
our
system
definition
so
that
�
E = K + Ug + Eother
and
�
Eother
includes
any
“other”
form
of
energy
that
might
have
been
produced

through
the
process
(most
of
it
is
thermal),
what
objects
are
included
in
this
system?
Discuss,
don’t
just
state
a
list.
c)
Determine
�
ΔEother
for
the
process
as
described.

d)
How
much
kinetic
energy
would
the
box
have
on
the
platform
if
�
ΔEother = 0
?
Phy 2201 page - 2 -
3) The system below consists of two masses attached through a
string of negligible mass
over a pulley that turns with negligible friction.
�
m1 > m2 and the sphere

�
m2 is immersed
in a viscous fluid that exerts a considerable drag force. Starting
from rest the system is set
into motion by releasing
�
m1 which causes this mass to descend while the other rises
(assume the string instantly becomes taut). In what follows
analyze the motion by
defining the “system” as both masses and Earth’s gravity field.
a) Once released each mass travels a distance
�
h1 and somewhere during this interval both
masses reach terminal speed
�
VT . Write out (derive/formulate) a mathematical expression
for the change of the potential energy of the system over this
interval (Using the givens!
Don’t make up numbers or define your own variable names.)
Has the system gained or
lost potential energy? Explain how you know.
b) Write out (derive/formulate) a mathematical expression for
the change in the kinetic
energy of the system over the
�

h1 interval (using the givens). Write out an expression for
the work done by the drag force over this interval using the
givens.
c) Following the
�
h1 interval the system moves a distance
�
h2 while the sphere is still
immersed in the fluid. Write out an expression for the work
done by the drag force over
this interval. Can you tell from this expression if the work done
by drag is positive or
negative? (You should.) Which is it and how do you know?
d) If
�
h1 = h2 over which interval does the drag force do more work in
an absolute value
sense? How do you know?
Phy 2201 page - 3 -
4) A 48 kg diver jumps off a cliff (with a running start) into the
ocean. The cliff is 50 m
above the ocean below. Her coach, using a video of the dive,
determines that at a point in

flight when she has risen 0.7 m above the cliff, her speed1
(center of mass) is 0.5 m/s.
Frictional effects such as drag are negligible.
Formulate your solution using the diver and Earth’s gravity
field as a system. Gravity
does not do work on this system. It’s effects are captured in
changes in potential energy.
a) How much kinetic energy did she have at takeoff? What was
her speed?
b) How much kinetic energy will she have as she splashes into
the ocean?
c) What minimum amount of chemical energy needed to be
consumed within the diver’s
body in order for her to walk to the cliff, from ocean level, and
then take off (jump)?
Explain how you know.
1 Includes both x and y velocity components. This is not the
highest point in the jump.