A rowboat is floating in a harbor, and a stubborn donkey pulls by mean of a long rope through a pulley the boat toward the shore. When the donkey has moved 1 meter, how far has the boat moved:
a) exactly 1 meter,
b) more than 1 meter,
c) less than 1 meter?
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Curiously enough, most people incorrectly answer that the boat moves
less than 1 meter.
The truth is the
boat moves MORE than 1 meter. I know, the answer seems paradoxical and counter-intuitive! But the visual geometric proof below will help you to understand why this happens.
According to “triangle inequality theorem” that states that for any triangle, the sum of the lengths of any two sides must be greater than to the length of the remaining side, we have:
QO < QQ’ + Q’O
QP + PO < QQ’ + Q’O
As
PO = Q’O
Thus
1 m = QP < QQ’
Q.E.D.
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