This question came up in a physics paper: there are two tracks A and B, with the direction of gravity specified. If two balls begin to move at the same uniform velocity at the same time, which of the two reaches the end of the track faster? enter image description here

A site(Physics UMD) says that the ball on B will advance and move further. But what's puzzling is that as the ball travels along the lowered platform, shouldn't it lose some velocity, so that it wouldn't be able to regain its original velocity ?

Thanks for checking this out!

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    $\begingroup$ I'm disregarding the last part about the ball losing speed. Instead of imagining inclines, it may help to imagine the track as completely flat, but with track B having a "boost" at the very beginning and an "anti-boost?" (I don't know what to call it) at the very end. Imagine the ball gets boosted to twice A's speed at the very beginning and slowed to A's speed at the very end. Then for almost the entirety of the track (except at the very beginning, and at the very end), it was traveling at twice the speed of A. So it'll take half the time. The inclines have the same effects as the boosts. $\endgroup$ Dec 14 '18 at 16:33
  • $\begingroup$ The experiment shows that the ball B comes first. We have to explain the experiment using mechanics. Perhaps the answer depends on the depth of the pit. If the pit is very deep ball A will come first. $\endgroup$ Dec 14 '18 at 17:09