Calculating Wave Speed in a String: Formula and Step-by-Step Guide

[Joza]

I am trying to find the speed of propagation of a transverse wave in a string.

Speed = wavelength times frequency.

I have the period, .075s, so 1 over T is the frequency.
I have the distance between 2 ADJACENT antinodes, which is .15m (Is this the wavelength?)

Could someone work out the speed so I can double check?

 

[Kurdt]

Two adjacent antinodes are half a wavelength apart.