Some corrections to the text
solution typos in chap 3...
From Eric Rimbey
Here are corrections for sections 3.4 & 3.5.
3.4 corrections:
1 (e) y(x) = -0.02296 x^2 + 1234 (negative sign was omitted)
3.4 additions:
4 (b) t = 0.6114 sec; x = 75.0375; y = -9.5458
(c) t = 0.6819 sec; x = 83.6916; y = -11.7621
3.5 corrections:
1 (f) 200.25 (last digit was inaccurate)
5 (a) a parenthesis is missing
(b) center: ( 10.116 , 20 )
white tip: ( 11.386 , 20.798 )
(inaccuracies in some of the final digits)
3.5 additions:
3 130 mph at 157.380 degrees
Here are my corrections and notes for section 3.2.
#1 (a) horizontal speed is given as -0.8, but later in the book a
distinction is made between speed (a positive number) and velocity
(vector). I suggest that the answer be given as just 0.8 ft/sec.
(b) text gives no answer. Distance from origin is 5.8138 ft
#3 (d) text gives no coordinates. These should be
(-14.2148 , -31.9834) in ft. Furthermore answer for time is not
accurate. It should be t=3.3347 sec.
#4 (a) Probably should note that the equation given indicates position
in feet (as opposed to yards). The use of different units caused a lot of
errors in this problem.
(b) correction: d=10.9768 ft = 3.6589 yds
(c) correction: ball is already on the green, so time entered green
is unknown. ball leaves green at t=16.8389 sec and at the point
(-42.1669 , -33.7335) in ft.
(d) y-coordinate given is inaccurate. should be y=0.3902 ft
(e) no answer given distance is:
sqrt(1476t^2/49 - 2904t/7 + 1460)
#5 No answers were given so I have provided some.
(a) x(t) = 9.9732t
y(t) = 0.7314t
(b) x(t) = 1500 + 9.9998t (t is time after leaving tower II)
y(t) = 120 - 0.06667t (t is time after leaving tower II)
(c) d=3004.06126 ft
(d) 1 min: (598.3931 , 43.8822)
4 min: (2395.9522 , 114.02699)
5 min: (2995.9388 , 110.02707)
(e) t=125.3357 sec at (1250 , 91.6667) and
t=200.4039 sec at (2000 , 116.6667)
(f) t=300.4061 sec
#7 (when and where) t=26.6403
Mike: (147.7739 , 221.6608) in ft
Tim: (161.7218 , 169.1391) in ft
(distance was not asked for but it is 54.3422 ft)
#8 (where and when closest to (3,4)) t=1.5
bug is at (3.2 , 4.4)
distance from (3,4) is 0.2 ft
(when is bug 6 ft from origin) t=3.5 sec
From: Eric Rimbey
Here are some more corrections:
pg 95, #18: the marble is blue
pg 261, #14: the launch angle is 75.96 degrees
the launch speed is 77.356 ft/sec
section 4.1:
no corrections
section 4.2:
3(a) inaccurate, pressure should be 14.34
5 (Note: My corrections to this problem are so different than the
given answers that I am worried that I did not understand
the problem correctly. I have triple-checked my work however,
so here are the corrections.)
(c) 20,106
(d) 5,521
Additions
4(a) 1st rate: 2176.00
2nd rate: 11,855,066.96
(b) 2nd rate is better if work >= 12 days.
From: Eric Rimbey
Here are some more corrections and additions:
Section 4.3
3(c) x = 0.3552
5(b) 34.6751 years
15 Note: I did not know what exercise 5.1.8 or 5.1.9 were. I
assumed that exercise 4.2.7 and 4.2.8 were intended.
(c) +- 159.128 feet
16(b) x > 81.49
17(f) 0.677 sec
21 17.38% downtime
22 12.29 years
Additions
6(a) A=5, b=1.77828
(b) 1.58114 liters
(c) altitude = 38.46541 meters (at time = 14.79588 sec)
(d) 0 liters (actually 5E-25)
8(a) 168.4159 years (sometime in 2051)
(b) 141.6325 years (sometime in 2024)
(c) 114.9381 years (sometime in 1997)
(d) yes
10(a) 1:10
(b) 7.72288
26(a) 8.80 cm
(b) 135.07 cm
(c) 4.84 years
From: Eric Rimbey
Section 4.4
1. 30 year loan monthly payment=1097.45
this is 297.78 more than monthly payments under 15 year plan
in first year of 30 year plan 1002.73 goes to principal and
12166.67 goes to interest
in first year of 15 year plan 4710.45 goes to principal and
12020.31 goes to interest
2. 393.48 should be 393.47
78441.12 should be 78441.13
3.(d) this question is unclear to me.
7.(c) the question should be clarified since the two plans being
compared use different interest rates.
13.(a) 182154.47
(b) 204839.89
(c) 201303.52
(d) 285721.57
Additions for section 4.4
9.(a) d=695.92
(b) B(12)=28288.39
(c) after 48 months
10.(a) B(336)=662157.65
(b) exceeds 500000 at 292 months
(c) when you are 88.737 years old
Section 4.5
additions
1.(a) age is about 32339 years
(b) 94.07%, died about 252 years ago
(c) a=-0.17329
2.(a) H=7.9672 days
(b) it takes about 26.5 days
(c) wait 26.5 days
Section 1.1
corrections
4. 49.94 should be 49.92
additions
7.(a) 117.0945 miles
(b) 0.2843 hours (about 17 minutes 3 seconds)
8.(a) port origin: (200,210), boat origin: (-100,710)
(b) (550,-425), (250,75)
(c) (300,-500), (0,0)
(d) (0,0), (-300,500)
Section 1.2
2. nothing given was incorrect but the question asked to provide
where circle intersects the axes.
x=0 => y=-5+5Sqrt(29) or y=-5-5Sqrt(29)
y=0 => x=20+10Sqrt(11) or x=20-10Sqrt(11)
Additions to Section 1.2
4. crosses E/W path at two points: 30+-10Sqrt(2) feet east of N/S path
8. (a) y=a for a<1 or a>3
(b) x=a for a<0 or a>2
(c) y=3 or y=1
(d) x=0 or x=2
(e) y=a for 1
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