Question

Mass of balls (grams): 10, 15, 26
Time to hit ground (seconds): 1.02, 1.01, 1.62
A student is investigating gravity and falling objects. She drops three balls and times how long it takes each ball to hit the ground. What is the most likely source of error?
A. She dropped the balls from different heights.
B. She did not measure the circumference of the balls.
C. She used balls that are different sizes.
D. She did not measure the mass after the balls hit the ground.

Answer 1

A. She dropped the balls from different heights.

Reason: For free fall (neglecting air resistance) time to fall depends only on height, not mass. The first two times (1.02 s and 1.01 s) match closely, but the third (1.62 s) is much larger, implying it was likely released from a greater height.