(5.0, -15)ġ2 Results for Case Study #2 And so we see that this second car is traveling a bit slower than the first one its velocity coming in with a magnitude of 9.0 m/s instead of 10 m/s. The value of the displacement drops from an original value of 30 m down to 15 meters. (0, 30) In the case of this graph, the rise is actually a drop. To find out, we must calculate the slope. Can you describe in words the motion of this car?ġ0 Case Study #2 If you said that this car approached you from in front, and then passed on by you, you were correct! It is also true that this car is traveling at a constant velocity (the graph line is straight.) But is it the same constant velocity the last car had?ġ1 Velocity from Slope It is the same velocity if the slope of the graph line is the same. (5.0, 20) Rise = x (1.0, -20) Run = tĩ Case Study #2 Here's a graph that describes the motion of another car you see while standing along the side of the road. The equation now becomes:Ĩ Finding the Velocity of Our Car Laying out a triangle on our graph helps us find the values for the rise and the run. rise runħ Slope as Velocity In this particular example, we have put time ( t) on the horizontal axis and displacement ( x) on the vertical axis. In this case, the line is straight, meaning that the slope (and hence, the velocity) remains constant for this automobile.Ħ Calculating the Slope In mathematics, the slope of a graph is expressed as the rise over the run.

time graph tells us the object's velocity. Car is behind you.ĥ Slope of Graph The slope of a displacement vs. time (s) displacement (m)Ĥ Graph for Case Study #1 Car is in front of you.

Positive displacements show that the car was in front of you. Negative displacements show that the car was behind you.

To graph the motion of this car, you will need some data.ģ The Data Table Using a stopwatch and roadside markers, you keep track of how far the car is from you (it's displacement) at each moment in time. Then the car passes you, disappearing off into the distance. An automobile approaches you from behind, traveling at a constant speed. Once you learn to read the graphs of the motion of objects, you can tell at a glance if the object in question was moving toward you, away from you, speeding up slowing down, or moving at constant speed.Ģ Case Study #1 Imagine you are standing by the side of the road.

1 Motion Graphs It is said that a picture is worth a thousand words.

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