Let the two balls roll down the slope, and note when they get to the bottom!
Тhe balls, even if starting from different positions get to the bottom of the slope at the same time.
The explanation is that the balls roll down a cycloid curve, on which it does not matter how heigh they are when they start, they need the same time to get down.
The strange phenomenon was noticed by the great Galilei. He started experimenting with a pendulum, and the time measuring tools of that age indicated that no matter how large is the amplitude of the oscillation, the pendulum swings back to its starting position in the same period of time.
As it turned out, the phenomenon is true in case of an object moving along a cycloid line.
A cycloid is the curve traced by a point on the rim of a circular wheel as the wheel rolls along a straight line.
