Question

Using the approximate conversion factors in Table 1.5, convert the following SI units to English units without using your calculator.

a. 30 cm b. 25 m/s

c. 5 km d. 0.5 cm

Short answer

Converting the given digits, we get,

a. $30cm\approx 12in$

b. $25m/s=50mph$

c. $5km=3mi$

d.$0.5cm=0.25in$

Step-by-step solution

Part a Step 1: Introduction

According to the table 1.5,

$10cm\approx 4in$

Now, we can convert the digit$30cm$following this relation.

Conversion of unit

The given digit should be written as,

$30cm\approx 30cm\left(\frac{4in}{10cm}\right)=12in$

Part b Step 1: Given data

According to the table 1.5,

$1m/s\approx 2mph$

Now, we can convert the digit $25m/s$following this relation.

Conversion of unit

The given digit should be written as,

$$\begin{gathered} 25m/s=25m/s\left(\frac{2mph}{1m/s}\right) \\ 25m/s=50mph \end{gathered}$$

Part c Step 1: Introduction

According to the table 1.5,

$1km\approx 0.6mi$

Now, we can convert the digit $5km$following this relation.

Conversion of unit

The given digit can be written as,

$$\begin{gathered} 5km=5km\left(\frac{0.6mi}{1km}\right) \\ 5km=3mi \end{gathered}$$

Part d Step 1: Given data

According to the table 1.5,

$10cm\approx 4in$

Now, we can convert the digit $0.5cm$following this relation.

Converting the unit

The given digits can be converted as,

$$\begin{gathered} 0.5cm=0.5cm\left(\frac{0.5in}{1cm}\right) \\ 0.5cm=0.25in \end{gathered}$$