# Waves and sound question

## Homework Statement

The speed of a transverse wave on a string is 420 m/s, and the wavelength is 0.14 m. The amplitude of the wave is 1.5 mm. How much time is required for a particle of the string to move through a total distance of 1.0 km?

λ x υ= v

## The Attempt at a Solution

λ x υ= v
υ= v/λ= 420/0.14= 3000
(1000meters)/(0.00152)= (4.444 x 108) T, where T is the period
t= (4.444 x 108)/ 3000= 1.481 x 10^5

i dont get what i'm doing wrong :(

berkeman
Mentor
Wow, are you and brookelynn3 in the same class? With the same typo in the question you're posting? How can a particle on the string move a km? Ok I don't know exactally what I am doing wrong here, someone please help! The speed of a transverse wave on a string is 400 m/s, and the wavelength is 0.19 m. The amplitude of the wave is 1 mm. How much time is required for a particle of the string to move through a total distance of 1.0 km?

I tried to solve for this by:
v=lamda/T so..
400=.19/t which equals a time of
.000475 seconds per cycle and i thought if I want 1000m (1km) i need to go 1000m/.19m to get how many cycles are necessary, that equals 5263.15 cycles to go 1000 meters so...
5263.15 cycles (.000475m/cycle)=2.5 seconds to complete all the cycles that equals 1000 meters or 1 km.
Except when I input this into my computer, its saying its wrong. can anyone pelase tell me what I am missing???

Astronuc
Staff Emeritus