A light ball is dropped straight down off a ledge and hits the ground. A heavy ball is thrown straight down from the ledge, released at the same height as the light ball and hits the ground. Which quantities are different for the two balls? I. time of flight II. acceleration III. velocity before impact (a) I (b) II (C) III (d) I and III (e) I, II, and III

(d) I and III

Explanation:

Motion of the 1st  light ball

I. Since the heavier starts with an initial velocity v0, and both balls end up traveling the same distance s. From the 2 motion equation above we can conclude that their time must be different

II. Both balls are affected by the same gravitational acceleration g

III. Velocity before the impact of the light ball

And the heavy ball

Since they have the same acceleration g and distance s. But the heavy ball has an initial push. It would end up with a larger speed.