Referring to the previous question,
(a) Is the change in the boulder's speed in one second greater than, less than, or equal to the change in speed of the pebble in the same time period?
(b) Choose the best explanation from among the following:
I. The large mass of the boulder results in a small acceleration.
II. The same force results in the same change in speed for a given time.
III. Once the boulder gets moving it is harder to stop than the pebble.