Chapter 3.3, Problem 37SP

Interpretation Introduction

Interpretation : The number of seconds in a 40-hour work week is to be calculated.

Concept Introduction : Dimensional analysis is a useful technique for resolving problems with the conversion of measurements from one unit to an equivalent measurement in another.

Answer to Problem 37SP

There are $\text{1}{\text{.44×10}}^{\text{5}}\text{secs}$ in exactly 40-hour work week.

Explanation of Solution

To convert hours into seconds, there should be two conversions.

At first, hours have to be converted into minutes and then minutes should be converted into seconds.

The known conversions are:

  $\begin{array}{c}\text{1}\text{hour}\text{=}\text{60}\text{mins}\\ \text{1}\text{min}\text{=}\text{60}\text{secs}\end{array}$

The unit conversion is given as:

  $\begin{array}{c}\text{40}\text{hour}\text{=}\text{40}\text{hr×}\frac{\text{60}\text{mins}}{\text{1}\text{hr}}\text{×}\frac{\text{60}\text{secs}}{\text{1}\text{min}}\\ \text{=144000}\text{secs}\\ \text{=}\text{1}{\text{.44×10}}^{\text{5}}\text{secs}\end{array}$

There are $\text{1}{\text{.44×10}}^{\text{5}}\text{secs}$ in exactly 40-hours.