 Fred |
 Lilly |
„Imagine a sphere, which is situated in a determined distance on the left of a very heavy wall which is fixed (see picture). What would the sphere "feel"? *
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„Well: sphere and wall attract each other because of their masses (gravitational force). For this reason, the sphere "feels" a force which pulls it towards the wall.“
„How could we "get rid" of this attractional force between the two bodies?“
„Aha! I see what you are aiming at. If the sphere did not "feel" any attractional force anymore ...“
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a) ... we would have to put a heavy and thick plate of metal between sphere and wall, to block the gravitational force off.
b) ... we would have to put a thick layer of foam between sphere and wall, to cushion the gravitational force.
c) ... we would have to exhaust the air because the gravitational force does not act in vacuum.
d) ... we would have to set up a second (similar) wall in the same distance on the left side of the sphere.
*To make it easier, only the forces which are exerting on the sphere are shown.
We take no account of counterforces (actio = reactio).