A big part of any physics class is spent solving word problems. This section will show you how to approach these problems.
Know your concepts. Later this will help you to identify what concepts are applicable. These concepts are often presented as variables in math models. You need to be able to identify what you are given in word problem. The first clue can be found in the units.
Physics has a set of units called fundamental units. These are units that cannot be described using other units. In kinematics the fundamental units are time and distance. Some variables in kinematics can be identified by the fundamental units while others are identified by the combination of the units. Below is a list of variables and their corresponding units.
| "x," |
length or distance, is measured using only distance units. |
| "v," |
velocity is measured using the fraction with a distance unit on top and 1 time unit in the bottom. |
| "a," |
acceleration is measured using the fraction with a distance unit on top and 2 time units in the bottom. |
| "t," |
time is measured using only distance units. |
If you see a number and unit combination like 4 m/s2 in a word problem you can recognize the 4 as an acceleration. This is because the units are a distance divided by two time units. If you see a unit like 6 m/s in a word problem, then you would recognize the number 6 a velocity because the units are a distance unit divided by a single time unit. But you do not know if this is an initial, final, or an average velocity. This piece of information is found by reading the word problem as if it were a story. In the story does the 6 m/s occur at the beginning or the end. If you are lucky the word problem tells you which velocity the number is by saying something like, "...the average velocity is 6 m/s."
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