Chapter 1, Problem 60QP

Interpretation Introduction

Interpretation:

The time required for the light to reach Earth from the Sun is to be calculated.

Concept introduction:

Dimensional analysis is a way to convert the units of measurement. In order to convert one unit to another, one needs to know the relationship between those units. These relationships are called conversion factors. Dimensional analysis is used to set up and solve a unit conversion problem using conversion factors.

Conversion factor is a fraction obtained from a relationship between the units. It is written as a ratio, and can be inverted to give two conversion factors for every relationship.

$1\text{ mi}=1609.34\text{ m}$, to convert mi to meter, the conversion factor is $\frac{1609.34\text{ m}}{1\text{ mi}}$.

$1\text{ min}=60\text{ s}$, to convert minute to second, the conversion factor is $\frac{60\text{s}}{1\min }$.

$\text{speed = }\frac{\text{distance}}{\text{time}}$ and $\text{time = }\frac{\text{distance}}{\text{speed}}$.