A 2-m long string is stretched between two supports with a tension that produces a wave speed equal to vw=50.00m/s. What are the wavelength and frequency of the first three modes that resonate on the string?

Respuesta :

Answer

given,

Length of the string, L = 2 m

speed of the wave , v = 50 m/s

string is stretched between two string

For the waves the nodes must be between the strings

the wavelength  is given by

           [tex]\lambda = \dfrac{2L}{n}[/tex]

where n is the number of antinodes; n = 1,2,3,...

the frequency expression is given by

            [tex]f = n\dfrac{v}{2L}[/tex]

now, wavelength calculation

      n = 1

           [tex]\lambda_1 = \dfrac{2\times 2}{1}[/tex]

                    λ₁ = 4 m

      n = 2

           [tex]\lambda_2 = \dfrac{2\times 2}{2}[/tex]

                   λ₂ = 2 m

      n =3

           [tex]\lambda_3 = \dfrac{2\times 2}{3}[/tex]

                    λ₃ = 1.333 m

now, frequency calculation

      n = 1

            [tex]f = n\dfrac{v}{2L}[/tex]

            [tex]f_1 =1\times \dfrac{50}{2\times 2}[/tex]

                    f₁ = 12.5 Hz

      n = 2

            [tex]f = n\dfrac{v}{2L}[/tex]

            [tex]f_2 =2\times \dfrac{50}{2\times 2}[/tex]

                    f₂= 25 Hz

      n = 3

            [tex]f = n\dfrac{v}{2L}[/tex]

            [tex]f_3 =3\times \dfrac{50}{2\times 2}[/tex]

                    f₃ = 37.5 Hz