In the video, I have put a coin on a white card and placed the whole coin-card system on top of the open end of a glass tumbler. When I flick the card suddenly, the coin falls inside the tumbler (In fact, I have shown it thrice in the video !). But when I move the card gently, the coin does not fall, but it also moves along with the card slowly. It is one of the most common Physics experiments I have ever seen !!

The question is really simple and as you expect. Why does the coin fall down when the card moves faster? And why does the coin not fall when the card moves slowly?
Well, a very popular explanation is that the coin does not move (only when the card moves with a great velocity) because of "Inertia" !! But I request you to contemplate on this explanation. I am not saying that it is wrong. But if it is a correct explanation, can it explain why we need to flick the card intensively? Why does "Inertia" not show its existence, while the card moves slowly? And can it predict a cut off velocity of the card to make the coin be inside the glass tumbler? So, in my opinion, it is a time to think of an alternative explanation !!

You can comment your answer !!

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