Travis sets up and experiment to determine and predict the velocity of a marble at the end of a track. He uses an electronic balance to weigh the marble and a set of calipers to measure the width of the marble. He then places the marble at the top of the track and releases it. Travis then uses the time it takes the marble to pass through a photogate at the bottom of the track to calculate the velocity of the marble. Travis notes that his prediction is significantly lower than his calculated velocity. Which error explains this difference?
A) He forgot to account for friction.
B) He forgot to zero the balance and found a weight for the marble that was too low.
C) He weighed the marble in a weighing dish and failed to account for the mass of the weighing dish.
D) He didn't position the photogate correctly and got the time required for the top of the marble to pass through, rather than to the middle.