Human Bone Youngs Modulus and Load Question

[ElBell]

Homework Statement

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?

Homework Equations

?

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

The Attempt at a Solution

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

I then get the answer 9* 10^8

I don't 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! :)

 

[pat666]

you can't use cm^2 your constant is in N/m^2, also you don't square it...

 

[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??

 

[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)?

Anyway, I also received an answer of 30000.

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

 

[pat666]

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

 

[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 :)