Two particle: one move along a straight line with a slope, and another one move along a curve as shown in the following applet.
Which one will arrive at the lower end earlier?
The simulation will stop at about t=2.0 s and you can click "play" button to find out the answer.
The most important thing to do is : Provide a good explanation with sound physics principle.

VIEW or DOWNLOAD ejs xml source
then click to translate strings for selected locale.

Press the Alt key and the left mouse button to drag the applet off the browser and onto the desktop.