A transverse wave described by equation `y=0.02sin(x+30t)` (where x and t are in meters and seconds, respectively) is travelling along a wire of area of cross-section `1mm^2` and density `8000kg//m^(3)`. What is the tension in the string?

Options

A. `20N`
B. `7.2N`
C. `30N`
D. `14.4N`

Answer

B

Explanation

`y=0.02sin(x+30t)`
for given wave, `v=(dx)/(dt)=-30`
`(x+30t=` constant)
We have `v=sqrt((T)/(mu))impliesT=muv^2=Arhov^2`
`=(10^-6m^2)(8xx10^3(kg)/(m^3))(30)^2`
`impliesT=7.2N`