Chapter 1.6, Problem 38E

To determine

To find:the change in elevation from $30\text{ metres to }-70\text{ metres}$

Answer to Problem 38E

The change in elevation from $30\text{ metres to }-70\text{ metres}$ is $-100\text{ metres}$

Explanation of Solution

Given information:

Initial elevation, ${\text{H}}_{\text{i}}=30\text{ metres}$

Final elevation, ${\text{H}}_{\text{f}}=-70\text{ metres}$

Calculation:

Subtract initial elevation from final elevation $\left({\text{H}}_{\text{f}}-{\text{H}}_{\text{i}}\right)$ to find the change in elevation,

  $\begin{array}{l}{\text{ H}}_{\text{f}}-{\text{H}}_{\text{i}}\\ =-70-30\left[{\text{Substitute values of H}}_{\text{f}}{\text{ and H}}_{\text{i}}\right]\\ =-70+\left(-30\right)\text{ [To subtract 30, add its opposite, }\left(-30\right)]\\ =-100\left[\text{Add}\right]\end{array}$

Hence, the change in elevation from $30\text{ metres to }-70\text{ metres}$ is $-100\text{ metres}$