Where necessary, use pi = 3,142 throughout this activity

The diameter ($D$) is $12 \text{ mm}$, which is $12 \times 10^{-3} \text{ m}$. The area ($A$) of a circular cross-section is given by $\pi \left(\frac{D}{2}\right)^2$. Use $\pi = 3.142$.

The force ($F$) is $30 \text{ kN}$, which is $30 \times 10^3 \text{ N}$.

Stress ($\sigma$) is force per unit area.

The change in length ($\Delta L$) is $0.3 \text{ m}$. The original length ($L$) is $2.4 \text{ m}$.

Strain ($\epsilon$) is the ratio of the change in length to the original length.