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The pressure inside a tire is measured as [tex]$28.0 \frac{\text{pounds}}{\text{inch}^2}$[/tex]. What is its pressure in [tex]$\frac{\text{newtons}}{\text{centimeter}^2}$[/tex]?

1 pound [tex]$= 4.45$[/tex] newtons

1 inch [tex]$^2 = 6.45$[/tex] centimeters [tex]$^2$[/tex]

Express the answer to the correct number of significant figures.

The pressure is [tex]$\square$[/tex] [tex]$\frac{\text{newtons}}{\text{centimeter}^2}$[/tex].



Answer :

To solve the problem of converting pressure from pounds per square inch to newtons per square centimeter, follow these steps:

1. Start with the given pressure:
The pressure inside the tire is given as [tex]\(28.0 \ \frac{\text{pounds}}{\text{inch}^2}\)[/tex].

2. Convert pounds to newtons:
We are given that [tex]\(1 \ \text{pound} = 4.45 \ \text{newtons}\)[/tex]. Therefore, multiply the given pressure by the conversion factor to change from pounds to newtons:
[tex]\[ 28.0 \ \frac{\text{pounds}}{\text{inch}^2} \times 4.45 \ \frac{\text{newtons}}{\text{pound}} \][/tex]

3. Convert inches squared to centimeters squared:
We are given that [tex]\(1 \ \text{inch}^2 = 6.45 \ \text{centimeters}^2\)[/tex]. To convert the area unit in the pressure measurement, we divide by the conversion factor:
[tex]\[ \frac{28.0 \ \text{pounds}}{\text{inch}^2} \times 4.45 \ \frac{\text{newtons}}{\text{pound}} \div 6.45 \ \frac{\text{centimeters}^2}{\text{inch}^2} \][/tex]

4. Combine and simplify the units:
[tex]\[ \text{Pressure in newtons per centimeter}^2 = \frac{28.0 \times 4.45}{6.45} \ \frac{\text{newtons}}{\text{centimeter}^2} \][/tex]

5. Calculate the numerical result:
Using the multiplications and divisions:
[tex]\[ = \frac{124.6}{6.45} \ \frac{\text{newtons}}{\text{centimeter}^2} \][/tex]
[tex]\[ = 19.3 \ \frac{\text{newtons}}{\text{centimeter}^2} \][/tex]

6. Rounding to the correct number of significant figures:
The initial pressure value, [tex]\(28.0 \ \frac{\text{pounds}}{\text{inch}^2}\)[/tex], has 3 significant figures. The final answer should also be expressed with 3 significant figures.

The pressure is [tex]\( \boxed{19.3} \ \frac{\text{newtons}}{\text{centimeter}^2} \)[/tex].