alameri (aoa434) – Hwk13 – Stokes – (19102)
1
This
printout
should
have
24
questions.
Multiplechoice questions may continue on
the next column or page – find all choices
before answering.
This is ONLINE HOMEWORK No 13. It
is due before 6.00 am on Tuesday 5 May, Abu
Dhabi Time (9.00 pm on Monday in Texas)
001
10.0 points
A harmonic wave is traveling along a rope.
The oscillator that generates the wave com
pletes 44
.
0 vibrations in 23
.
2 s. A given crest
of the wave travels 411 cm along the rope in a
time period of 10
.
3 s.
What is the wavelength?
Correct answer: 0
.
210397 m.
Explanation:
Let :
n
= 44
.
0 vibrations
,
t
= 23
.
2 s
,
Δ
x
= 411 cm = 4
.
11 m
,
and
Δ
t
= 10
.
3 s
.
λ
=
v
f
=
Δ
x
Δ
t
n
t
=
t
Δ
x
n
Δ
t
=
(23
.
2 s)(4
.
11 m)
44 (10
.
3 s)
=
0
.
210397 m
.
002
(part 1 of 3) 10.0 points
A transverse wave of frequency 25 Hz propa
gates down a string. Two points 15 cm apart
are out of phase by
7
π
3
.
What is the wave length of the wave?
Correct answer: 12
.
8571 cm.
Explanation:
Let :
Δ
x
= 15 cm
and
δ
=
7
π
3
.
Let the positive
x
direction be the direction
of propagation of the wave.
The phase difference is
δ
= 2
π
Δ
x
λ
λ
= 2
π
Δ
x
δ
= 2
π
15 cm
7
π/
3
=
12
.
8571 cm
.
003
(part 2 of 3) 10.0 points
At a given point, what is the phase difference
(as a multiple of
π
) between two ‘displace
ments for times 5 ms apart?
Correct answer: 0
.
25
π
.
Explanation:
Let :
t
= 5 ms = 0
.
005 s
and
f
= 25 Hz
.
The period is
T
=
1
f
, so the phase difference
is
δ
= 2
π
t
T
= 2
π t f
= 2
π
(0
.
005 s) (25 Hz)
=
0
.
25
π
.
004
(part 3 of 3) 10.0 points
What is the wave velocity?
Correct answer: 3
.
21429 m
/
s.
Explanation:
v
=
f λ
= (25 Hz) (12
.
8571 cm)
parenleftbigg
1 m
100 cm
parenrightbigg
=
3
.
21429 m
/
s
.
keywords:
005
10.0 points
The figure shows two wave pulses that are
approaching each other.
P
Q
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
alameri (aoa434) – Hwk13 – Stokes – (19102)
2
Which of the following best shows the shape
of the resultant pulse when the centers of the
pulses, points
P
and
Q
, coincide?
1.
2.
3.
correct
4.
5.
Explanation:
Notice that the two pulses have the same
width and amplitude.
Choosing the the point
P
(the same as point
Q
when the two pulses coincide) as the origin,
the two pulses can be described as:
P
:
y
1
=
A
,
−
d
≤
x
≤
d
Q
:
y
2
=
braceleftBigg
A
,
−
d
≤
x <
0
−
A
,
0
< x < d
Using the principle of superposition, the re
sultant pulse is
y
=
y
1
+
y
2
=
braceleftbigg
2
A
,
−
d
≤
x <
0
0
,
0
< x < d
P
Q
P
+
Q
006
10.0 points
A 2
.
5 kg block supported by a string rests on
a frictionless incline. The length of the string
This is the end of the preview.
Sign up
to
access the rest of the document.
 Spring '09
 NAJAFZADEH
 mechanics, Work, Correct Answer

Click to edit the document details