YOU NEED
It is well known fact that if you rest a ruler one on each end of your extended forefingers, and if you move them towards each other they will perforce meet at the centre of the ruler. The explanation is simple. Should one finger travel ahead of the other, the weight on that particular finger increases.
Therefore, it raises the friction between the ruler and the finger. This in turn lowers the friction on the other finger allowing it to travel ahead. Now the question is: In a situation where both fingers are at the centre of the ruler, what is likely to happen should you move them back to the ends of the ruler. Trying guessing the answer before you try the experiment. You are likely to be surprised.
HOW DOES IT WORK?
When one finger begins to move, its friction
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