Unit analysis involves changing units (like converting from inches to feet) for a measured quantity (like the length of a soccer field). Being able to perform unit analysis is very important, as you will use it again in later labs as well as in daily life. Below are some examples to demonstrate how this works. Example 1: Your professor says you have 2.5 hours to complete an exam. You know that there are 60 minutes in an hour, and 60 seconds in a minute. How many seconds do you have to complete the exam? Answer: 2.5 hours x- 60 minutes 1 hour 60 seconds 1 minute 2.5 hours x 60 minutes 1 hour Also note that conversions can be written equivalently with the numerator and denominator flipped. For example: 60 seconds 1 minute Problem-solving steps: (1) We wrote down the quantity given in the question (2.5 hours). (2) We included the conversion between hours and minutes (there are 60 minutes in 1 hour) and minutes and seconds (there are 60 seconds in 1 minute). (3) We multiplied all of the numbers together to obtain the answer and cancelled out units. - 9000 seconds Notice that you can cross out repeated units that appear in both the top and bottom of fractions (in this case it is "hour" that can be crossed out), and the unit(s) for the resulting answer are the unit(s) that remain. 60 minutes 1 hour can also be written as 1 hour 60 minutes You know that there are 60 seconds in 1 minute, 60 minutes in 1 hour, 24 hours in 1 day, and about 365 days in 1 year. How many seconds are in 1 year? Keep track of all units and show all work. You will use this result in the next few questions.