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Curved Line Velocity-Time Graphs
Let's look at one final aspect of velocity-time graphs. What does it mean when the line is not straight but rather looks more like part of a parabola?
Take a look at the velocity-time graph above. Notice that it is a curved line rather than a straight line.
What does that tell us about the object's velocity speed and direction or acceleration change in velocity ? Let's discuss the answers to this question.
Velocity and the Curved Line v-t Graph
What can we determine about the object's velocity from this graph?
The velocity of the object is increasing, but it is not increasing at a constant interval (if it was, the line would be straight). The part of the curve that is steeper (highlighted below) indicates a greater change in velocity.
Acceleration and the Curved Line v-t Graph
What can we determine about the object's acceleration from this graph?
We know the object is accelerating due to the slope of the line. However, because this line is a curve, we know the object's acceleration is not constant.
The object's acceleration is not uniform. At some points (the steeper parts of the curve), the object is accelerating faster than at the less steep parts of the curve (highlighted below).
d-t Graphs vs. v-t Graphs
As a final note, please be careful when you are interpreting different graphs of motion! You will notice that the velocity-time graphs look very similar to the displacement-time graphs, but the slope of the lines have different meanings.
Before you ever answer a question about a graph, make sure to look at the x-axis and y-axis labels to know which type of graph it is!
Notice that both of these graphs have a similar shape. However, one is a displacement-time graph and one is a velocity-time graph. You can tell which is which by looking at the labeled axes.