The scientific explanation of why it is impossible to catch a dollar bill with two fingers

If someone offers to easily earn $ 20 in a simple game - just catch a falling dollar bill with two fingers, in any case does not settle, it's a trap!

The denomination fall between the fingers, and you will not be able to catch her. Moreover, it is not capable of any one person. The fact biological limitations: most people's reaction time is about 0, 2

. The trick is that one can easily demonstrate the trick itself: to give up the bill with one hand and catch the fingers of the other hand, because the brain gives the command before the other hand left a piece of paper. If you try to catch a dollar bill, thrown by another person, then nothing happens.

In the last podcast Numberphile from the Research Institute of Mathematical Sciences (MSRI) this topic in detail reveals Tokieda Tadashi (Tadashi Tokieda).



The signal from the brain to the muscles finger comes near 0, 2. The question is, how far in that time have time to fly paper. The distance D is determined by the formula:

D = ½ gt2,

where t - time, g - free fall acceleration

. On the surface of the Earth at a latitude of 45 ° 5 g at sea level is, as you know, 9, 8 m / s2.

If we substitute these values ​​into the formula, we get the following:

D = 0, 5 * 9, 8 * 0, 22 0, 196 m,

that is, a little less than 20 centimeters.

By measuring the dollar bill, you can easily make sure that its length is 15, 5 cm, so that people are not physically able to react. Even the person with the best reaction fingers adjoin 4 centimeters higher when the bill is already fly down.

Source: geektimes.ru/post/275894/