A net force of 200 N acts on a 100-kg boulder, and a force of the same magnitude acts on a 100-g pebble.
(a) Is the change of the boulder's momentum in one second greater than, less than, or equal to the change of the pebble's momentum in the same time period?
(b) Choose the best explanation from among the following:
I. The large mass of the boulder gives it the greater momentum.
II. The force causes a much greater speed in the 100-g pebble, resulting in more momentum.
III. Equal force means equal change in momentum for a given time.