A student measures the time 
for a ball to fall from rest through a vertical distance 
. Knowing that the equation 
applies, the student plots the graph shown.
Which of the following is an explanation for the intercept on the axis?
Air resistance has not been taken into account for larger values of .
There is a constant delay between starting the timer and releasing the ball.
There is an error in the timer that consistently makes it run fast.
The student should have plotted against 
