contestada

Bone has a Young's modulus of about
1.8 x 100 Pa. Under compression, it can
withstand a stress of about 1.59 x 108 Pa be-
fore breaking.
Assume that a femur (thigh bone) is 0.53 m
long, and calculate the amount of compression
this bone can withstand before breaking.
Answer in units of mm.

Respuesta :

Answer:

505.62 mm

Explanation:

Young's modulus of a material is given by,

[tex]Y=\frac{Stress}{Strain}[/tex]

Stress is the force experienced by the material per unit area (which is why stress has the same units as pressure).

Strain is the ratio between the change in length/area/volume to the original length/area/volume of the material (and hence a dimensionless quantity). Basically, it gives us a measure of the change in dimensions due to the stress experienced.

So, for the given problem,

[tex]Y=\frac{Stress}{\Delta L/L}[/tex]

or, [tex]1.8\times100=\frac{1.59\times108}{\Delta L/0.53}[/tex]      (since we need to find the compression of the bone at the critical stress point)

or, [tex]\Delta L=\frac{1.59\times108\times0.53}{1.8\times100} m=0.50562m=505.62mm[/tex]