Human Bone Youngs Modulus and Load Question

1. May 26, 2010

ElBell

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

A human bone has a youngs modulus of 10^10 N m^-2. It fractures when the compressive strain exceeds 1%. What is the maximum load that can be sustained by a bone of cross sectional area 3cm^2?

2. Relevant equations???

F= Y*(change in length/ original length)* cross sectional area

3. The attempt at a solution

F= (10*10^10)* (1/100)* (3^2)

I then get the answer 9* 10^8

I dont understand what units I am supposed to use...and if this answer appears correct or not.

Can anyone shed any light? Have I done this correctly?

TIA! :)

2. May 26, 2010

pat666

you cant use cm^2 your constant is in N/m^2, also you dont square it.......

3. May 26, 2010

pat666

i get 30000N newtons is the unit from your actual question
ps Y is 10^10 not 10*10^10 could be a typo??

4. May 26, 2010

ElBell

When I take onboard the tips you have given me, I get the same answer as you! I thought (10* 10^10) was the same as (10^10)???

Is that the final answer? Do I need to do something with the results? Isnt that too big?

5. May 26, 2010

pat666

not really sure what you mean, that is the answer.... units of force are Newtons. and who did you recieve an answer form... teacher???

6. May 26, 2010

ElBell

No I didnt receive an answer from teacher, I formulated it myself but it appears I didnt get it right!

Thanks so much for your help, I know I am lacking the basic knnowledge for this but I am doing my best :)