How Does Material Change Affect Wave Speed in a Slinky?

[runicle]

The speed of a slinky

Questions:
i What happens to the speed of the wave if the material changes (ex. stretched)
ii What happens to the speed of a pulse is reflected off one end of the material.

 

[siddharth]

runicle, what's the formula for a speed of a wave on a string? Can you express it in terms of its mass per unit length and its tension?
So what happens to the tension and mass per unit length if the string is stretched?