Summary: Students will be expected to know the International System of Units (SI) for physical quantities, recognize the difference between dimensional and unit analysis, the difference between fundamental and derived units, and perform unit conversions.

Students will be able to…

1. Know the SI units for physical quantities.
2. Differentiate between dimensional analysis and unit analysis.
3. Differentiate between fundamental and derived units.
4. Convert between units.

In this class, we will default to SI (International System of Units), which are derived from dimensions. SI units are sometimes calles MKS (meters, kilograms, seconds). Here's a nice tabulation of SI units:

Here's an example that uses Newton's second law $\Sigma \overrightarrow{F} = m\overrightarrow{a}$, which you'll see in Forces. Let's determine the units of $\overrightarrow{F}$ by looking at dimensions:

$$\Sigma \overrightarrow{F} = m\overrightarrow{a} \to [M]\frac{[L]}{[T]^2}$$ So $N$ has units of $\frac{kg*m}{s^2}$.

Conversions

Easy (No Powers)

Let's convert 100 feet per second to ? kilometers per day:

= 2633 km/day

Less Easy (Powers)

Now, what if we go from $10 m^3 \to cm^3$? There are 100 cm per 1 meter, so use that to "cancel out" the $m^3$:

=

= $10*10^6 cm^3$

Unit Conversion - No Powers (4 min)

Tutorial on unit conversions

Basic unit conversions.

Let us know if you find any simulations for units.

Unit conversion practice (with solutions).

Units are how we measure physical quantities. Think of units as a "measuring stick" which lets us make physical sense of the universe around us. In this class, we will use SI (International System of Units) as our base units. You've probably learned tricks for this in your chemistry class, so feel free to use those here. Just make sure we know what you're doing!