Video Transcript
A blue object and an orange object
move across a grid of lines spaced one meter apart. Each object moves for two
seconds. The arrows show the distances that
the objects move in each second. What is the speed of either object
relative to the grid lines that it crosses?
Here, we are asked to find the
speed of either object when measuring the position of that object relative to the
grid lines that it is crossing. We are told that the grid lines are
each one meter apart. And we can see that each object
passes a total of two grid lines. Each object must then travel a
distance of two meters. We are also told that each object
moves for two seconds.
All the grid lines are
stationary. This means that the motion of an
object toward or away from a grid line is the only thing that affects the speed of
an object relative to the grid line. We see then that the equation for
the speeds of the objects will just depend on the changes in distance of the
objects.
Remember that the speed of an
object is the distance traveled by an object divided by the time that the object
travels for. In our question here, both objects
travel two meters in two seconds. Therefore, the equation for speed
for each of the objects will be that their speed is equal to two meters divided by
two seconds. When we simplify this, we get the
speed of the objects is one meter per second. This is the speed of either object
relative to the grid lines that it crosses.
