Science and Mathematics for Engineering 6th Edition by John Bird

Exercise 19

The modulus of elasticity $E$ is given by the formula: $E = \frac { F L } { x A }$ where $F$ is force in Newton's, $L$ is the length in metres, $x$ is the extension in metres and $A$ the cross-sectional area in square metres. Evaluate $A$ , in square centimetres, when $\mathrm { E } = 80 \times 10 ^ { 9 } \mathrm {~N} / \mathrm { m } ^ { 2 } , \mathrm { x } = 2 \mathrm {~mm} , \mathrm {~F} = 100 \times 10 ^ { 3 }$ and $\mathrm { L } = 2.0 \mathrm {~m}$