# Simple question about young's modulus

by lionely
Tags: modulus, simple, young
 P: 489 I did a practical worked the gradient and calculated E, of a wooden metre rule. What I want is a value to compare my value with, I got 5 N/m2 So 5N will bend the ruler 1m? Seems likely right?
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PF Gold
P: 10,193
 So 5N will bend the ruler 1m? Seems likely right?
Well - presumably you'd reach the elastic limit of the ruler before then.
Though your argument does not seem to match the units...

Compare:
 P: 489 On that page isn't that Mega Pascals?? I got 5Pa
P: 489

## Simple question about young's modulus

and maybe on that page those are MUCH higher maybe cause they calculated it using woods of greater thickness,length, etc.
 P: 489 Ohhhh LOL i'm sorry I didn't even see what I typed my mind was away. I didn't mean 5 newtons would bend it 1m
 Homework Sci Advisor HW Helper Thanks PF Gold P: 10,193 Would you get a higher modulus if you used a thicker beam? It's a material property. How is the modulus defined? You can also look for other people who've done the same and talked about it. It's a common enough experiment - done either by vertical deflection by weights or by Timing harmonic motion.
 P: 489 I found out my value is very wrong D: I need to recheck my calculations
 P: 489 I am so stupid =.= I left off a 10^-8 somewhere in my calculations. New value which makes sense NOW is 5.10 x 10^7Pa.
 P: 489 Sigh again i was wrong I did it over again I got 5,108.1 MPa
 Homework Sci Advisor HW Helper Thanks PF Gold P: 10,193 When you have measurements on such a wide variation of scales, it is very easy to misplace lots of zeros :) You can see from the discussion of accuracy in the article that these can get very big (as much as 56% it says) so you only need the right order of magnitude. "Conclude: Youngs modulus for a wooded meter-rule was experimentally determined to be _____GPa. This agrees to the same order of magnitude as an accepted value of _____GPa given in ref. ______." If you did errors then you can also comment on how good the agreement was.
 P: 489 Thank you.

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