How Much Must You Stretch a Guitar String to Obtain a Tension of 10 N?

[kavamo]

Homework Statement

A 0.46 m long guitar string, of cross-sectional area 1.1 10-6 m2, has Young's modulus Y = 2.20 109 N/m2. By how much must you stretch the string to obtain a tension of 10 N?

Homework Equations

?

The Attempt at a Solution

I don't know how to begin this problem. What is Young's modulus, and how is it used?

 

[payumooli]

youngs modulus is the ratio of stress to strain

stress is given in force/unit area

strain change in dimension/original dimension (no units)

all values are given except change in dimension

 

[kavamo]

so do I use hooks law?

F/A=Y delta L/L

I got it! The answer is 1.9 mm.

Thanks!

 

[RoyalCat]

so do I use hooks law?

F/A=Y delta L/L

Yep. That's using the definition of Young's Modulus!

Isolate your unknown variable, \Delta \ell as a function of all your known variables, F, A, \ell, Y and just stick all the values into the formula you get.