Video Transcript
What is the speed shown by the
speed–time graph?
In this question, we’ve been given
a speed–time graph. Recall that we can use such a graph
to represent the motion of an object by plotting what its speed is as time goes
on. Let’s say that this red line on the
graph represents the motion of some object. Here, we want to know the object’s
speed. So let’s start by taking a closer
look at the graph to see what we can learn from it.
Well, we can see that the vertical
axis represents the speed at which the object is traveling in meters per second, and
the horizontal axis shows us the time that the object is traveling for in
seconds. Now, notice that the red line on
the graph is horizontal. On a speed–time graph, a horizontal
line means that as time goes on, the speed of the object doesn’t change. The value of speed is constant.
To find what speed this is, all we
have to do is read the value that the red line corresponds to on the vertical or
speed axis. Notice that on either axis, the
side length of each grid square represents one unit, so starting at zero and moving
up along the vertical axis, we can count that the red line is at one, two, three
meters per second. So this must be our answer. The speed shown by the speed–time
graph is three meters per second.
