Question

Suppose that the maximum amount of tensile stress a ligament can endure before breaking is 500 Pascals (Pascal = N/m²). If the total area of the ligament is 0.05 m², what is the maximum tensile force it can endure before breaking? Show your work.

6. For Problem 5, suppose that total area of the ligament is now 0.2 m², what is the maximum tensile force it can endure before breaking? Show your work.

7. Suppose the maximum strain of a tibia is 0.0035 during normal walking. How much length change can we expect to see in a tibia that is 15 cm long?

8. The tibia is the major weight-bearing bone in the lower extremity. If 88 % body mass is proximal to the knee joint, how much compressive force acts on each tibia when a 500 N person stands in anatomical position? How much compressive force acts on each tibia if the person holds a 30 N sack of groceries? Show your work.

Answer 1

5.

Tensile strength is the stress at which a force applied causes the material to lengthen then break. For an axially load material the breaking strength in tension is s=P/a where s is the breaking strength , P is the force that can cause it to break and a is the cross sectional area

Here Tensile stress before breaking = s= 500 pascles

cross sectional area =a = 0.05m2

Max tensile force P= ?

As we know, s=P/a

P= s x a =500 x 0.05 = 25N

6. s=500 pascles

a = 0.2 m2

therefore, P= s x a = 500 x 0.2 = 100N