How to Interpret Velocity Time Graphs
- 1). Determine whether the line is horizontal. If it is, the object is moving at a constant velocity. You can find that rate by looking at the point where the line crosses the y-axis. In this case, the acceleration is 0.
- 2). Notice whether the line is straight, but not horizontal. If it is, then the object is accelerating at a constant rate. You can tell the object's velocity at any given time by first drawing a vertical line from the given time on the x-axis to the line, then drawing a horizontal line from that point to the y-axis. You can tell the acceleration by finding the slope of the line. To do this, pick any two points on the line, then divide the difference in the y-values (the velocities) by the difference in the x-values (the times).
- 3). Ask whether the curve is a regular function, such as a polynomial or a trigonometric function. Unfortunately, there is no easy way to do this: you need experience and knowledge of many functions. In any case, you can still tell the velocity by the same method as in step 2. If you can identify the function that represents the curve, then you can determine the acceleration by differentiating the function, using calculus. If you cannot identify the function, then you can only estimate the acceleration.
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