Final answer:
Both balls will take the same time to fall because vertical motion is independent of horizontal motion in the context of gravity's influence, assuming no air resistance is present.
Step-by-step explanation:
If a ball is thrown horizontally at the same moment, and from the same height, that an identical ball is dropped straight down, how would you compare the times they spent falling? The correct answer is C. Both will take the same time to fall. This question involves the concept of projectile motion and the independence of vertical and horizontal motions under the influence of gravity. According to the principles of physics, the vertical motion is independent of the horizontal motion. This means that gravity acts on both balls equally, causing them to fall at the same rate, regardless of any horizontal velocity one of the balls may have. The vertical component of their velocity is solely influenced by gravity, which is the same for both balls.
It's important to note that air resistance is ignored in this idealized scenario. In reality, air resistance might affect the times, but under the typical simplifications used in physics problems, it is not considered. Consequently, the ball that is thrown horizontally and the one that is simply dropped will hit the ground at the same time if released from the same height.