Site for children

J. Perelman
"Entertaining physics". Book 2.
Chapter 3. Circular motion


To prove his innocence , you will be not as easy as you might think. Imagine that you really were on "devil's swing" and you want to convince your neighbors that they are wrong. Invite you to join in this debate with me. We will sit with you on the "devil's swing", wait for the moment when swinging, it will, apparently, to describe the full circles, and define the debate that swirls: swing or the whole room? Please keep in mind that during an argument we should not leave the swing; all necessary bring in advance.

You. How can you doubt that we are stationary and spinning room! After all, if our swing really upside down, then we would not hung upside down, and would have fallen from the bore. But we don't fall. So, not spinning swing, and bathroom.

I. However, rememberthat the water of the rapidly whirling bucket comes, though it is tipped upside down. Cyclist in "the devil's loop" (see next) also does not fall, though, and goes upside down.

You. If so, calculate the centripetal acceleration and make sure that there is enough for it, so we did not fall out of the swing. Knowing our distance from the axis of rotation and the number of revolutions per second, we can easily determine by the formula...

I. Do not bother to calculate. The organizers of the "devil's swing", knowing about our dispute, and warned me that the speed would be sufficient that the phenomenon was explained in my opinion. Therefore, the calculation will not resolve our dispute.

You. However, I have not lost hope to convince you. See, the water from this glass is not poured on the floor... However, you and here I will refer to the experience with rotating bucket. Well: I hold in my hand a plumb - he all the time is aimed at our feet, i.e. down. If we turned, and the room remained motionless, plumb would be all the time turned to the floor, i.e., pulled it to our heads to the side.

I. Wrong: if we move fast enough, the plumb all the time should be discarded from the axis along the radius of rotation, so back to our feet, as we observe.

Entertaining physics J. Perelman


System Orphus


Did you like our site and you would like to support it? It's very simple: tell your friends about us!

  © 2014 All children