Physics Sensemaking

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Section 1.7 Physics Sensemaking

Physics is fundamentally about using quantitative models to make sense of the natural world. When you make sense of something, your objective is evaluate whether or not what physics says about a context aligns with your physical understanding and reasoning about that context. The steps in the following figure will guide you in making sense of physics.

Physics Sensemaking. Step 1: Based on your physical understanding of the situation, what do you expect to be true? Justify your answer! Step 2: What does the symbolic equation say about the situation? Show how it says this explicitly! Step 3: Check to see if the symbolic equation agrees with your physical understanding! — Figure 1.7.1. Steps to follow when sensemaking.

Exercises Practice Activity

1. Driving to Portland.

You drive from Corvallis to Portland, and you measure your gas tank (in gallons) as a function of time (in hours):

\begin{equation*} G(t) = G_o - \beta t^2 \end{equation*}

1. For each symbol in this equation ($G\text{,}$ $t\text{,}$ $G_o\text{,}$ $\beta$):

Describe what the symbol represents in words.
Determine the units of the symbol.

2. Graph the function by hand.

Clearly label the axes and any important features.
Where are Corvallis and Portland on your graph?
What are the advantages of graphing a function like this by hand? What advantages would you gain if you had used a graphing calculator instead?

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