D. When playing violin different notes can be produced depending on the position of the fingers one hand on the string. The usual technique presses the string hard against the fingerboard, reducing the length of the string that can vibrate. If we consider this string initially tuned to an A4 and a finger is placed one third of the length down from the tuning peg: What would be the new fundamental frequency, i.e., the frequency of the new note being produced assuming the same tension as in A above? i. What would be the new frequency of the note, if instead of using the technique described above for violin playing, the technique called artificial harmonic is used, where only partial pressure is put on the string so that it produces a knot on the string? Hint: the following llustration may be useful to you.

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I need help with part D, i and ii please :)

A violin string of L-31.8 cm in length and u=0.64gm/linear mass density is tuned to play an A4
note at 440.0 Hz. This means that the string is in its fundamental oscillation mode, i.e., it will be on
that note without placing any fingers on it. From this information,
A. Calculate the tension on the string that allows it to be kept in tune.
Given: The length of the violin string is 31.8 cm or 0.318 m.
The linear mass density is 0.64 g/m or 0.64 x 10³ kg/m.
The frequency is 440.0 Hz.
To determine: (a) The tension in the string
For the string fixed at both ends
n²=L
where L is the length of the string and A is the wavelength.
Rearrange the above equation for >
λ =
For the fundamental mode, n = 1
λι = 2L
The speed is
v=f₁2₁
(1)
where v is the speed of the wave on string, f, is the frequency
Substitute the value of λ, in equation (1)
v = f₂2L
(2)
The expression for speed of the wave on string is
V=
(3)
where T is the tension
From equation (2) and (3)
=f,2LSquaring on both sides = f,2L²
The tension from above equation is
T = 4f²L²μ
Substitute 0.64 x 103 kg/m for u, 440.0 Hz for f, and 0.318 m for L in the above equation
T = 4 x 440 Hz³0.318 m² x 0.64 x 10³ kg/mT = 50.1 N
The tension in the string is 50.1 N.
B. If from the midpoint of the string a maximum transverse motion 2.59 mm is observed
when it is in the fundamental mode, what is the maximum speed vy máx of the string's
antinode?
(b) The maximum speed vy, max
The maximum speed of the antinode
Vy, max
= Aw₁
(4)
where w₁ is the angular frequency and A is the amplitude of the wave
w₁ = 2πf₁
Substitute w, in equation (4)
Vy, max
= A2πf₁
The amplitude is 2.59 mm or 0.00259 m.
Vy, max
= 0.00259 m X 2π X 440.0 Hzvy, max = 7.16 m/s
The maximum speed vy, max is 7.16 m/s.
C. If the string tension is reduced by 6.3% of the tension found in A, what is the resulting
frequency of the note produced?
(c) The resulting frequency when the string tension is reduced by 6.3 % of the tension found in A
The new tension in the string is
T'T-6.3 IT¹ = 0.937 T
100
The frequency is
f = ¹
√
2L
0.937 T
f =
2L √
H
Substitute 0.64 x 103 kg/m for μ, and 0.318 m for L and 50.1 T for T in the above equation
f=
0.937x50.1 T
= 425.8 Hz
0.64 x 10 kg/m
2x0.318 m
The resulting frequency when the string tension is reduced by 6.3 % of the tension found in A is 425.8 Hz.
Transcribed Image Text:A violin string of L-31.8 cm in length and u=0.64gm/linear mass density is tuned to play an A4 note at 440.0 Hz. This means that the string is in its fundamental oscillation mode, i.e., it will be on that note without placing any fingers on it. From this information, A. Calculate the tension on the string that allows it to be kept in tune. Given: The length of the violin string is 31.8 cm or 0.318 m. The linear mass density is 0.64 g/m or 0.64 x 10³ kg/m. The frequency is 440.0 Hz. To determine: (a) The tension in the string For the string fixed at both ends n²=L where L is the length of the string and A is the wavelength. Rearrange the above equation for > λ = For the fundamental mode, n = 1 λι = 2L The speed is v=f₁2₁ (1) where v is the speed of the wave on string, f, is the frequency Substitute the value of λ, in equation (1) v = f₂2L (2) The expression for speed of the wave on string is V= (3) where T is the tension From equation (2) and (3) =f,2LSquaring on both sides = f,2L² The tension from above equation is T = 4f²L²μ Substitute 0.64 x 103 kg/m for u, 440.0 Hz for f, and 0.318 m for L in the above equation T = 4 x 440 Hz³0.318 m² x 0.64 x 10³ kg/mT = 50.1 N The tension in the string is 50.1 N. B. If from the midpoint of the string a maximum transverse motion 2.59 mm is observed when it is in the fundamental mode, what is the maximum speed vy máx of the string's antinode? (b) The maximum speed vy, max The maximum speed of the antinode Vy, max = Aw₁ (4) where w₁ is the angular frequency and A is the amplitude of the wave w₁ = 2πf₁ Substitute w, in equation (4) Vy, max = A2πf₁ The amplitude is 2.59 mm or 0.00259 m. Vy, max = 0.00259 m X 2π X 440.0 Hzvy, max = 7.16 m/s The maximum speed vy, max is 7.16 m/s. C. If the string tension is reduced by 6.3% of the tension found in A, what is the resulting frequency of the note produced? (c) The resulting frequency when the string tension is reduced by 6.3 % of the tension found in A The new tension in the string is T'T-6.3 IT¹ = 0.937 T 100 The frequency is f = ¹ √ 2L 0.937 T f = 2L √ H Substitute 0.64 x 103 kg/m for μ, and 0.318 m for L and 50.1 T for T in the above equation f= 0.937x50.1 T = 425.8 Hz 0.64 x 10 kg/m 2x0.318 m The resulting frequency when the string tension is reduced by 6.3 % of the tension found in A is 425.8 Hz.
D. When playing violin different notes can be produced depending on the position of the fingers of
one hand on the string. The usual technique presses the string hard against the fingerboard,
reducing the length of the string that can vibrate. If we consider this string initially tuned to an A4,
and a finger is placed one third of the length down from the tuning peg:
i. What would be the new fundamental frequency, i.e., the frequency of the new note being
produced assuming the same tension as in A above?
ii. What would be the new frequency of the note, if instead of using the technique described
above for violin playing, the technique called artificial harmonic is used, where only partial
pressure is put on the string so that it produces a knot on the string? Hint: the following
illustration may be useful to you.
Nut
Bridge
12th Fret
1/2
1/6
1/7
1/5
7th Fret
1/3
5th Fret
1/4
Node
Transcribed Image Text:D. When playing violin different notes can be produced depending on the position of the fingers of one hand on the string. The usual technique presses the string hard against the fingerboard, reducing the length of the string that can vibrate. If we consider this string initially tuned to an A4, and a finger is placed one third of the length down from the tuning peg: i. What would be the new fundamental frequency, i.e., the frequency of the new note being produced assuming the same tension as in A above? ii. What would be the new frequency of the note, if instead of using the technique described above for violin playing, the technique called artificial harmonic is used, where only partial pressure is put on the string so that it produces a knot on the string? Hint: the following illustration may be useful to you. Nut Bridge 12th Fret 1/2 1/6 1/7 1/5 7th Fret 1/3 5th Fret 1/4 Node
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