# Waves traveling through a string

1. Jan 22, 2009

### j88k

1. The problem statement, all variables and given/known data

A string of length L vibrates at its fundamental frequency. The amplitude at a point (1/4) L from one end is 6.00 .

What is the amplitude of each of the traveling waves that form this standing wave?

2. Relevant equations

none

3. The attempt at a solution

I absolutely don't know where to start. Have to submit it as soon as possible and I'm running out of options.

2. Jan 23, 2009

### rl.bhat

In the standing wave, the displacement of the particles of the string is given by
y(x,t) = A*sin(kx)*cos(wt). For all the particles cos(wt) remains constant. When kx = 0, the point is node. When kx = pi/2, the point is anti node, which is at the middle of the string. At L/4, kx must be pi/4. Now find A.

3. Jan 23, 2009

### j88k

what goes for y(x,t) and cos(wt) then?

4. Jan 23, 2009

### j88k

anyone ?

5. Jan 23, 2009

### rl.bhat

what goes for y(x,t) and cos(wt) then?
y(x,t) is the vertical amplitude if the vibrating particle and (wt) is the angular velocity of the particle which is same for all particles.

6. Jan 24, 2009

### j88k

sorry for being extremely shallow, but what it (wt) ?

I looked everywhere and I can't seem to find the constant.

7. Jan 24, 2009

### rl.bhat

w = 2*pi/T where T is the time for one oscillation. It is constant for all particles. And t is the time.