# Why does a bullet fall?

## Department of Education and Psychology

For two years we studied the phenomenon of eastward deviation of spheres falling from great heights to demonstrate the rotation of the earth.

If the earth is not rotating, there is no deviation at all, since the only force that acts on the sphere is the gravitational force that pulls it vertically downwards.

But if one assumes a rotation of the earth, a coherent thought that occurred to us and other people earlier is that the sphere must have a west deviation:

If you assume that an object thrown from a high tower falls straight down while the earth continues to rotate (the earth rotates counterclockwise when viewed from the North Pole), the object would have to hit west of the tower.

This idea can also be well understood using the example of a moving ship. Assuming an object is dropped from a mast of a non-moving ship, it hits directly below the mast. However, if the ship moves, the object hits the rear end of the ship. The point of impact in this case also depends on how fast the ship is traveling.

But since there apparently does not seem to be any deviation, the experiment in Galileo's time was viewed as evidence against an earth rotation.

Galileo resisted this interpretation and refuted this assumption by referring to the inertia of the crowd. Inertia is the property of bodies to offer resistance to a change in speed or direction of movement.

Even a ball that falls from the top of a tower pushes further in the direction of the earth's rotation, while being pulled down by the gravitational force of the earth at the same time when it is dropped. And this movement in the direction of the earth's rotation is sufficient, according to Galileo, that the ball shows no deviation when it hits the ground.

However, he assumed that the base of the tower was just as fast as the top of the tower. However, in the case of a rotation, an object located outside has a higher speed than an object which is close to the axis of rotation. Because depending on where an object is in relation to the axis of rotation, it has to cover more or less distance in the same time.

Afterwards, personalities such as Newton, Guglielmini, Benzenberg, Flammarion and Reich carried out further drop tests.

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