In physics lab, Piper attaches a wireless sensor to one of the spokes of a bicycle wheel spinning freely on its axle. The graph below shows the sensor's height above the ground, in centimeters, over time t, measured in seconds.
What is the midline and what does it represent in this context?
0
Time (in seconds)
Sensor's height (in cm)
t
h
0
Time (in seconds)
Sensor's height (in cm)
(2.5, 73)
(6.5, 73)
(4.5, 25)
(0.5, 25)