pasha (sep635) – HW #12 – Antoniewicz – (56445)
1
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30
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001 (part 1 of 7) 3.0 points
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
,
25 m
,

650 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
=
r
f

r
i
Δ
t
.
Because
r
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 (part 2 of 7) 3.0 points
What is
v
y
in m/s?
Correct answer:

55 m
/
s.
Explanation:
The average velocity of the spacecraft is
calculated by finding the change of position
over a change in time:
¯
v
=
r
f

r
i
Δ
t
.
Because
r
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
=
(25 m)

(300 m)
(5 s)
=

55 m
/
s
003 (part 3 of 7) 2.0 points
What is
v
z
in m/s?
Correct answer:

50 m
/
s.
Explanation:
The average velocity of the spacecraft is
calculated by finding the change of position
over a change in time:
¯
v
=
r
f

r
i
Δ
t
.
Because
r
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
=
(

650 m)

(

400 m)
(5 s)
=

50 m
/
s
004 (part 4 of 7) 4.0 points
What is

v

in m/s?
Correct answer: 86
.
8907 m
/
s.
Explanation:
The magnitude is calculated by:

v

=
v
2
x
+
v
2
y
+
v
2
z
=
(45 m
/
s)
2
+ (

55 m
/
s)
2
+ (

50 m
/
s)
2
=
86
.
8907 m
/
s
005 (part 5 of 7) 3.0 points
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pasha (sep635) – HW #12 – Antoniewicz – (56445)
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
.
517892.
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

v

For example:
ˆ
v
x
=
v
x

v

=
45 m
/
s
86
.
8907 m
/
s
=
0
.
517892
006 (part 6 of 7) 3.0 points
What is ˆ
v
y
?
Correct answer:

0
.
632979.
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

v

For example:
ˆ
v
y
=
v
y

v

=

55 m
/
s
86
.
8907 m
/
s
=

0
.
632979
007 (part 7 of 7) 2.0 points
What is ˆ
v
z
?
Correct answer:

0
.
575435.
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

v

For example:
ˆ
v
z
=
v
z

v

=

50 m
/
s
86
.
8907 m
/
s
=

0
.
575435
008 (part 1 of 7) 3.0 points
Here are the positions at three di
ff
erent
times for a bee in flight (a bee’s top speed is
about 7
m/s .
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 Fall '08
 Turner
 Velocity, Trigraph, Equals sign, 2007 albums

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