Question

What is the conversion?

Answer 1

Answer:

  see below

Step-by-step explanation:

The conversion factor in the box is the product ...

  $\dfrac{1\,\text{kPa}}{1000\,\text{Pa}}\cdot\left(\dfrac{1\,\text{m}}{100\,\text{cm}}\right)^3=10^{-9}\,\dfrac{\text{kPa m}^3}{\text{Pa cm}^3}$

_____

The purpose of a conversion factor is to multiply by 1 in the form of a ratio that changes the units. We know that 1000 Pa = 1 kPa, so the ratio (1 kPa)/(1000 Pa) is the ratio of two equal quantities. It has the value 1 and will change units from Pa to kPa.

Likewise, 100 cm = 1 m, so (1 m)/(100 cm) will change the units from cm to m. However the given expression uses cm³, so we need to multiply by the conversion factor 3 times. That factor is ((1 m)/(100 cm))³ = (1 m³)/(10⁶ cm³).

To choose the appropriate conversion factor, look at the units you have (Pa, cm) and the units you want (kPa, m). Find the relationship these have to each other, and write the ratio so that it will cancel the units you have and leave the units you want.

When SI units are involved the prefixes help you out. k = kilo = 1000; c = centi = 1/100. It is worthwhile to get to know them.