Site for children

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


Thousands of people play in childhood with the top, not many will be able to answer this question. As, in fact, to explain the fact that rotating top, vertical or even inclined, not tipped, contrary to all expectations? What force holds it in such a seemingly unstable position? Unless the weight has no effect?

Here is a very interesting interaction forces. The theory of the spinning top is not easy, and delve into it we won't. Let us outline the main reason why a spinning top does not fall.

Figure 26 depicts a top, rotating in the direction of the arrows. Note the part And its rim and a portion Inopposite her. Part And is keen to move away from you, part of the In - to you. Watch now, what movement get these parts, when you tilt the axis of the spinning top by yourself. The boost you get the part And move up, part of the In - down; both parts get a push at right angles to their movement. But as with the rapid spinning of the top circumferential speed of the disk is very large, then we inform you a minor speed, adding to the large circular velocity point, gives ravnodeystvuiushchey, very close to this circular, and the movement of the top is almost unchanged. It's understandable why the top as would resist the attempt to overturn. The more solid the top and the faster it spins, the harder he counteracts the tilting.

Why the top doesn't fall?

The essence of this explanation is directly related to the law of inertia. Each particle of the top moves on a circle in the plane perpendicular to the axis of rotation. According to the law of the inertia of the particle at each moment tends to go with the circle on a straight line tangent to the circle. But every tangent is located in the same plane as the circle itself; therefore, each particle tends to move so that all the time to stay in the plane perpendicular to the axis of rotation. It follows that all the planes in the top, perpendicular to the axis of rotation, strive to maintain its position in space, and therefore the total perpendicular thereto, i.e., the very axis of rotation also tends to maintain its direction.

Rotating top, being planted, preserves the original direction of its axis.

Will not consider all motions of the top, which occur under the influence of external forces. It would require too detailed explanations, which, perhaps, will seem boring. I only wanted to explain the reason for the desire of every rotating body to keep the direction of the axis of rotation.

This property is widely use modern technology. Various gyroscopic (based on the property of a spinning top) gauges - compasses, stabilizers, etc. are installed on ships and aircraft. [Rotation ensures stability of shells and bullets in flight, and can also be used to ensure the sustainability of space missiles, satellites and missiles during their movement (Approx. as amended).]

This is a useful use of the seemingly simple toys.

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