When do two pulses begin to meet?

[tigers4]

Homework Statement

A 140 g wire is held under a tension of 200 N with one end at x = 0 and the other at x = 7.0 m. At time t = 0, pulse 1 is sent along the wire from the end at x = 7.0 m. At time t = 30.0 ms, pulse 2 is sent along the wire from the end at x = 0. At what position x do the pulses begin to meet?

Homework Equations

v=sqrt(T/DENSITY)

The Attempt at a Solution

I assume you set two equations equal, but am unsure how to use the information given to find where they meet

 

[ojs]

Well, they have the same velocity that you give, but in the opposite direction. Try not to think about them as pulses but as two objects (like cars or something similar) moving towards each other with that velocity and see if you can find some kinematic equation to solve for where the two objects meet. See also if you need to use 7-x instead of x in one of the equations (so you get the distance from the origin for the first object).

 

[Fewmet]

You could also find the relative velocity of Pulse 2 with respect to Pulse 1 and put the situation in the perspective of Pulse 1. The question then becomes "When does Pulse 2 arrive at x=0 m? (Then you'd have to convert back to the original reference frame.)