Unit analysis or dimensional analysis is a method used to calculate values based on the units of each measurement. We will start by using this method to simply convert one measurement in one unit to another unit. This technique may seem more complicated than necessary at this point, but remember you are learning how to use the units. Later in the semester you will see that unit analysis will make problem solving so much easier!
Unit analysis is based on two very fundamental mathematical principles.
- any number multiplied by one is equal to itself
- a fraction equals one if the value of the numerator equals the value of the denominator
These two properties allow us to let the measurements determine how to do the calculation. The final answer must have the units desired and all other units must be canceled.
When using the railroad, how many significant digits do you use in your answer?
ReplyDeleteYou use the sig dig rules. 1.69 has 3, 2.54 has 3 and the rest are exact numbers, therefore in this problem you should have 3 sig digs in your final answer.
ReplyDeletehow do you know whether or not to put the answer in sci not?
ReplyDeleteA number has to be in sci not if it is greater than 1000, or 10^3, OR very small, LESS than 0.01 or 10^-2.
ReplyDeleteSo, 0.003 MUST be in sci not, but 0.03 shouldn't be.