Video Transcript
Emma walks to school every day. Find her speed from the
distance-time graph.
Notice on the 𝑥-axis, we have the
time in minutes and on the 𝑦-axis, we have the distance in metres. We are asked to find her speed. And speed is equal to distance
divided by time. So we can go through and pick any
distance, say 400. And then we divide by the
corresponding time.
So we go over to our line. And we find that the 400 meters
goes with the five minutes. And now, we simplify. 400 divided by five is 80. So this means Emma’s speed would be
80 meters per minute. Now, we also could have used a few
other points. However, there aren’t very many
other points that go through the light grey lines on our graph.
For example, if we would pick 200
meters and then try to find what time went with that, we would see that it would be
around two and a half. But we couldn’t exactly guess. It’s better to have an exact amount
to land on. So this is why it’s good to choose
the 400 meters and the five minutes.
Overall, once again, Emma’s speed
was 80 metres per minute.
