schopper (as55864) – Ch1HW2 – Antoniewicz – (56465)
1
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30
questions.
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before answering.
001(part1of7)1.429points
A spacecraft is observed to be at loca
tion
(
200 m
,
300 m
,
−
400 m
)
relative to an
origin
located
on
a
nearby
asteroid,
and
5 s later it is observed to be at location
(
425 m
,
75 m
,
−
700 m
)
.
Find the average ve
locity of the spacecraft, ¯
v
=
(
v
x
, v
y
, v
z
)
.
What is
v
x
in m/s?
Correct answer: 45 m
/
s.
Explanation:
The average velocity of the spacecraft is
calculated by finding the change of position
over a change in time:
¯
v
=
vectorr
f
−
vectorr
i
Δ
t
.
Because
vectorr
is a vector, the average velocity will
also be a vector and each component must be
calculated separately.
For ¯
v
x
the value becomes:
¯
v
x
=
v
2
x
−
v
1
x
Δ
t
=
(425 m)
−
(200 m)
(5 s)
=
45 m
/
s
002(part2of7)1.429points
What is
v
y
in m/s?
Correct answer:
−
45 m
/
s.
Explanation:
The average velocity of the spacecraft is
calculated by finding the change of position
over a change in time:
¯
v
=
vectorr
f
−
vectorr
i
Δ
t
.
Because
vectorr
is a vector, the average velocity will
also be a vector and each component must be
calculated separately.
For ¯
v
y
the value becomes:
¯
v
y
=
v
2
y
−
v
1
y
Δ
t
=
(75 m)
−
(300 m)
(5 s)
=
−
45 m
/
s
003(part3of7)1.429points
What is
v
z
in m/s?
Correct answer:
−
60 m
/
s.
Explanation:
The average velocity of the spacecraft is
calculated by finding the change of position
over a change in time:
¯
v
=
vectorr
f
−
vectorr
i
Δ
t
.
Because
vectorr
is a vector, the average velocity will
also be a vector and each component must be
calculated separately.
For ¯
v
z
the value becomes:
¯
v
z
=
v
2
z
−
v
1
z
Δ
t
=
(
−
700 m)
−
(
−
400 m)
(5 s)
=
−
60 m
/
s
004(part4of7)1.429points
What is

vectorv

in m/s?
Correct answer: 87
.
4643 m
/
s.
Explanation:
The magnitude is calculated by:

vectorv

=
radicalBig
v
2
x
+
v
2
y
+
v
2
z
=
radicalBig
(45 m
/
s)
2
+ (
−
45 m
/
s)
2
+ (
−
60 m
/
s)
2
=
87
.
4643 m
/
s
005(part5of7)1.429points
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schopper (as55864) – Ch1HW2 – Antoniewicz – (56465)
2
Find the unit vector in the direction of the
velocity of the spacecraft, ˆ
v
=
(
ˆ
v
x
,
ˆ
v
y
,
ˆ
v
z
)
.
What is ˆ
v
x
?
Correct answer: 0
.
514496.
Explanation:
The unit vector for a vector is given as :
ˆ
v
=
(
ˆ
v
x
,
ˆ
v
y
,
ˆ
v
z
)
=
(
v
x
, v
y
, v
z
)

vectorv

For example:
ˆ
v
x
=
v
x

vectorv

=
45 m
/
s
87
.
4643 m
/
s
=
0
.
514496
006(part6of7)1.429points
What is ˆ
v
y
?
Correct answer:
−
0
.
514496.
Explanation:
The unit vector for a vector is given as :
ˆ
v
=
(
ˆ
v
x
,
ˆ
v
y
,
ˆ
v
z
)
=
(
v
x
, v
y
, v
z
)

vectorv

For example:
ˆ
v
y
=
v
y

vectorv

=
−
45 m
/
s
87
.
4643 m
/
s
=
−
0
.
514496
007(part7of7)1.429points
What is ˆ
v
z
?
Correct answer:
−
0
.
685994.
Explanation:
The unit vector for a vector is given as :
ˆ
v
=
(
ˆ
v
x
,
ˆ
v
y
,
ˆ
v
z
)
=
(
v
x
, v
y
, v
z
)

vectorv

For example:
ˆ
v
z
=
v
z

vectorv

=
−
60 m
/
s
87
.
4643 m
/
s
=
−
0
.
685994
008(part1of7)1.429points
Here are the positions at three different
times for a bee in flight (a bee’s top speed is
about 7
m/s .
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 Fall '08
 Turner
 Velocity, Orders of magnitude, Equals sign, 2007 albums

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