This preview shows pages 1–3. Sign up to view the full content.
Problem 2.1
(a) The average speed in this case is a weighted average
()
hr
km
9
.
52
hr
250
.
0
hr
750
.
0
hr
200
.
0
hr
500
.
0
hr
750
.
0
hr
km
0
.
40
hr
200
.
0
hr
km
.
100
hr
500
.
0
hr
km
0
.
80
=
+
+
+
⎟
⎠
⎞
⎜
⎝
⎛
+
⎟
⎠
⎞
⎜
⎝
⎛
+
⎟
⎠
⎞
⎜
⎝
⎛
=
avg
v
(b) The total distance traveled is
km
90
hr
250
.
0
hr
750
.
0
hr
200
.
0
hr
500
.
0
9
.
52
=
+
+
+
⎟
⎠
⎞
⎜
⎝
⎛
=
=
hr
km
t
v
d
tot
avg
Problem 2.4
The average speed of the Olympic marathon record is
(
)
(
)
hr
mi
1
.
12
s
3600
hr
1
s
21
min
60
hr
1
min
9
hr
2
yd
1760
mi
1
yd
385
mi
26
=
⎟
⎠
⎞
⎜
⎝
⎛
+
⎟
⎠
⎞
⎜
⎝
⎛
+
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
+
=
avg
v
Problem 2.19
(a) The average acceleration of the plane off the
Stennis
when the plane was
initially at rest is
2
0
s
ft
103
s
2.50
s
3600
hr
1
mi
1
ft
5280
hr
mi
175
=
⎟
⎠
⎞
⎜
⎝
⎛
⎟
⎠
⎞
⎜
⎝
⎛
⎟
⎠
⎞
⎜
⎝
⎛
=
=
=
+
=
t
v
a
at
at
v
v
(b) The distance that the plane moves is
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document()
ft
322
s
50
.
2
s
ft
103
2
1
2
1
2
1
2
2
2
2
0
=
⎟
⎠
⎞
⎜
⎝
⎛
=
=
+
=
Δ
at
at
t
v
x
Problem 2.21
The time that it takes the car to accelerate from 55 mph to 60 mph is
s
7
.
3
s
m
0.60
hr
mi
1
s
m
447
.
0
This is the end of the preview. Sign up
to
access the rest of the document.
 Summer '08
 MEITZLER
 mechanics, Heat

Click to edit the document details