## SAT Physics Conventions and Graphing - Summary

1. FUNDAMENTAL AND DERIVED UNITS. The fundamental metric units are for the basic units of measure, such as length, mass, and time. As formulas are created with these smaller units, derived units will result. You should know the fundamental unit components of derived units. You can do this by replacing quantity symbols in a physics formula with their fundamental units to determine the derived unit.
2. HOW A GRAPH IS PLOTTED AND TITLED. The dependent variable is plotted on the y-axis, and the independent variable is plotted on the x-axis. The title of a graph always lists the dependent variable first and the independent variable second.
3. THE IMPORTANCE OF SLOPE. The slope of a line is determined by dividing the rise (y-axis value) by the run (x-axis value). Whenever you see a graph with units listed on its axes, you should immediately divide the units and see if their quotient is a unit with some significance. For example, the slope of a position (meters) versus time (seconds) graph will have units in meters per second. The slope is therefore the velocity.
4. THE IMPORTANCE OF AREA. The area under a line segment can be determined by multiplying the rise (y-axis value) by the run (x-axis value). The areas encountered in beginning physics will be zero, rectangular, triangular and/or trapezoidal. Areas below the x-axis are negative. Multiplying the units listed on the axes will indicate their significance. For example, the area of a velocity (m/s) versus time (s) graph will have units in meters. This area represents displacement.
5. USING A GRAPH TO PREDICT THE FUNCTION THAT CREATED IT. Plotting a function based on a physics equation will produce one of four likely curves: Linear, quadratic, square root, and inverse. You should become familiar with the basic shapes of these four likely curves and then be able to associate them with physics equations. Save