Question

a sttel wire of diameter 1mm can supporta tension of 0.2kn. a cable to support a tension of 20kn should have a diameterv of what order of magnitude

Answer 1

$$\frac{F_2}{F_1}=\frac{A_2}{A_1}=\frac{d_2^2}{d_1^2}$$

$$\frac{20}{0.2}=\frac{d_2^2}{1^2}$$

$$d_2=10\ mm$$