Question #1188d

2 Answers
LucaGasparro
Jan 8, 2018

Some measurements are not compatible.

Explanation:

The simple answer is that it wouldn't make sense to mix different types of units. For example, take #cm# and #m#. While they both take on the measurement of length, if I wanted to find the area of #cm# by #m# square, it wouldn't look right to mix the units to get #cmm# therefore we convert both to one or the other. Sometimes conversions make the numbers a lot more nicer to work with as well.

Steve J.
Jan 9, 2018

There are many reasons -- such as what your first answer mentioned. Another case is when you would be multiplying a measurement times a coefficient which has units.

Explanation:

An example of the case I mentioned above involves density. Density is mass/volume and is typically found in units of #(kg)/m^3#. If you know the volume of an object in cubic centimeters, or cc, it would be wrong to multiply the density by volume with those units.

Assume your data is a density with units of #"kg"/m^3# and volume of an object in units of cc. First convert the volume units from cc to #m^3#. Then when you multiply the density by the volume, the #m^3# units of the volume will cancel the #m^3# in the denominator of the density, leaving you with kg.

I hope this helps,
Steve

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