Chapter 1, Problem 1.31P

(a)

Interpretation Introduction

Interpretation:

The area of a telescope lens in square feet $\left({\text{ft}}^2\right)$ is to be calculated.

Concept introduction:

The area is a physical quantity and its SI unit is meter square $\left({\text{m}}^{\text{2}}\right)$. The area of an object is equal to the product of the length and breadth of the object. Length and breadth of an object are measured in the units of length. Therefore, the area has the unit of length to the square power. The other unit of the area are centimeter square, milliliter square, kilometer square.

The conversion of one unit into another can be done using a proper conversion factor. Conversion factors are the ratios that relate the two different units of a quantity. It is also known as dimensional analysis or factor label method.

In the unit conversion problems, the given information is multiplied by the conversion factors to obtain the desired information. The unit conversion can be done as follows:

$\left(\cancel{\text{beginning unit}}\right)\left(\frac{\text{Final unit}}{\cancel{\text{beginning unit}}}\right)=\text{Final unit}$

(b)

Interpretation Introduction

Interpretation:

The time taken to polish the entire lens is to be calculated.

Concept introduction:

The area is a physical quantity and its SI unit is meter square $\left({\text{m}}^{\text{2}}\right)$. The area of an object is equal to the product of the length and breadth of the object. Length and breadth of an object are measured in the units of length. Therefore, the area has the unit of length to the square power. The other unit of the area are centimeter square, milliliter square, kilometer square.

The conversion of one unit into another can be done using a proper conversion factor. Conversion factors are the ratios that relate the two different units of a quantity. It is also known as dimensional analysis or factor label method.

In the unit conversion problems, the given information is multiplied by the conversion factors to obtain the desired information. The unit conversion can be done as follows:

$\left(\cancel{\text{beginning unit}}\right)\left(\frac{\text{Final unit}}{\cancel{\text{beginning unit}}}\right)=\text{Final unit}$