Ch1H2 – florin – (56950)
1
This printout should have 30 questions.
Multiplechoice questions may continue
on the next column or page – find all
choices before answering.
001 (part 1 of 7) 3.0 points
A spacecraft is observed to be at location
h200 m, 300 m, −400 mO relative to an origin
located on a nearby asteroid, and 5 s later it
is observed to be at location h475 m, 100 m,
−650 mO . Find the average velocity of the
spacecraft, v¯ = hv
x
, v
y
, v
z
O .
What is v
x
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
.
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
t
=
(475
m) − (200
m) (5 s)
=
55 m/s
3
(part 2 of 7) 3.0 points
What is v
y
in m/s?
Correct answer:
−40 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
.
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
t
=
(100
m) − (300
m) (5 s)
=
−40 m/s
4
(part 3 of 7) 3.0 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
.
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
t
=
(−650 m) − (−400 m)
(5 s)
=
−50 m/s
5
(part 4 of 7) 2.0 points
What is ~v in m/s?
Correct answer:
84.4097 m/s.
Explanation:
The magnitude is calculated by:
q
~v =
v
x
2
+ v
y
2
+ v
z
2
q
=
(55 m/s)
2
+ (−40 m/s)
2
+ (−50 m/s)
2
=
84.4097 m/s
5
(part 5 of 7) 3.0 points
This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentCh1H2 – florin – (56950)
2
Find
the
unit
vector
in
the
direction
of
the
For example:
velocity of the spacecraft, vˆ = hvˆ
x
, vˆ
y
, vˆ
z
O .
vˆ
z
=
v
z
What is vˆ
x
?
~v
=
−50 m/s
Correct answer:
0.651584.
84.4097 m/s
Explanation:
=
−0.592349
The unit vector for a vector is given as :
hv
x
, v
y
, v
z
O
008 (part 1 of 7) 3.0 points
vˆ = hvˆ
x
, vˆ
y
, vˆ
z
O =
Here
are
the
positions
at
three
di
f
erent
~v
times for a bee in flight (a bee’s top speed is
For example:
about 7m/s .
vˆ
x
=
v
x
T ime
P osition
~v
9.5 s
h−2.5 m, 10.4 m, 0 mO
55 m/s
10 s
h−0.3 m, 7.2 m, 0 mO
=
84
.4097 m/s
10.5 s
h1.5 m, 2.7 m, 0 mO
=
0.651584
Between 9.5 s and 10 s, find the bee’s aver
006 (part 6 of 7) 3.0 points
age velocity:
A
A
A
What is vˆ
y
?
v¯
= hv
x
, v
y
, 0O .
Correct answer:
This is the end of the preview.
Sign up
to
access the rest of the document.
 Spring '08
 Turner
 Momentum, Velocity, Correct Answer, Orders of magnitude, 2007 albums

Click to edit the document details