Video Transcript
If the speed of an object changes
as the object moves, is the speed of this object uniform?
This question asks us whether a
changing speed can be a uniform speed. If an object moves uniformly, this
means that in any two equal time intervals that the object travels for, the distance
that the object travels in each time interval is equal.
Let’s consider the uniform motion
of a bicycle. We can see the position of the
bicycle at different distances. We can see that the distances
between these positions are all equal to 10 meters. We can see that the time intervals
between these times are all equal to one second.
Recall that the speed of an object
is the distance that the object travels divided by the time that the object travels
for. We can see then that in each time
interval, the speed of the object is 10 meters per second. The question is asking about an
object that changes speed as it moves. If the object changes speed, then
the speed of the object in different time intervals can be different.
For this bicycle, the distances
moved in each time interval are still 10 meters, but the speed in each time interval
is different. This means that the time intervals
cannot be equal. So we can see that if an object
changes speed, it cannot be moving equal distances in equal time intervals. Therefore, the object cannot be
moving uniformly.
