The slide

Toy cars go down a sloped lane (inclined plane).
Over three hundred years ago, Galileo Galilei claimed that such a slide is the same as a fall, with the exception of being slower. As if the force of gravity was weaker (distributed into components).

At the end of the inclined plane they turn upside down, like a swimmer at the end of a lane, and they by no means slow down. It seems they bounce off.

The last car is charged by a piece of lead but this does not make it go faster. If a bike goes down a slope, it accelerates like a car. It was also noticed by Galileo.