Deathloop

HOW

1. Place a ball anywhere on the inclined plane and release it freely. Watch how it moves.
2. Try to find the starting points of the ball on the plane that allow the different behaviour of the ball in the loop to be observed:

• the ball rises to a certain
height and then rolls away,
remaining in the loop,

• the ball falls from the
top of the loop, and

• the ball travels the entire loop.

WHY

There are two forces acting on the ball in the loop: the gravitational force (directed vertically downwards) and the centrifugal force (directed outwards from the loop).

In order for the ball to travel the entire loop, the value of the centrifugal force must be greater than the value of the gravitational force at the highest point of the loop. The centrifugal force depends on the mass of the ball, the radius of the loop (these quantities do not change) and the square of the ball speed. The condition for passing the loop will therefore be for the ball to achieve a sufficiently high speed.