Site for children

J. Perelman
"Entertaining physics". Book 1.
Chapter 2. Gravity and weight. A lever. Pressure


Asking someone this question, of course, you will receive the answer: “Forward motion, according to the law of inertia”. Ask, however, to explain more, and here the law of inertia. You can predict what will happen: your partner will surely prove my point; but if not to kill him, he soon he will stop wondering: will that it is because of inertia it is necessary to jump on the contrary - back against the movement!

Indeed, the law of inertia plays a minor role, the main reason was different. And if this is the main reason to forget, that we really come to the conclusion that you need to jump backward, and not forward.

Let you need to jump on the go. What happens when you do this?

When we jump out of a moving car, our body, being separated from the car, has the speed of the car (it moves by inertia) and is keen to move forward. Making a leap forward, of course, we do not destroy this speed, but, on the contrary, is still increasing.

It follows that we need to jump back, not forward, in the direction of movement of the carriage. Because when we jump back to the speed reported by the jump, is subtracted from the speed at which our body moves by inertia; therefore, touching the earth, our body with less force will seek to overturn.

However, if you have to jump from a moving crew, we all jump forward motion. It really is the best way and so proven that we strongly caution readers against attempts to check the inconvenience phrygana ago with the moving crew.

So what's the deal?

Of infidelity explanation, in his reticence. Will jump forward, will jump back - in either case we are in danger of falling, as your upper body will still move when the legs touching the ground, stop [Can explain the fall in this case also from a different point of view. The speed of this movement when jumping forward even more than when you jump back. But it is essential that forward to fall is much safer than falling back. In the first case, we as usual putting the foot forward (while at high speed the car run a few steps) and the preventable fall. This movement habitually , as we all his life by his walking because from the point of view of mechanics, as we learned from the previous article, the walk is not that other, as the number of drops in our body forward, preventable placing feet. In the fall the same back no saving this foot traffic, and because the danger is much greater. Finally, it is important that even when we really fall forward, then, holding hands, ressybusa not like when you fall on your back.

Now, the reason that it is safer to jump out of the car forward, lies not so much in the law of inertia, but in ourselves. It is clear that for objects inanimate rule is not applicable: bottle thrown from the car ahead is more likely to shatter if dropped, rather than thrown in the opposite direction. So if you have some reason to jump out of the car, throwing a previously your Luggage, you should throw the baggage ago, by the same jump forward.

People experienced the tram conductors, inspectors often do: jump back, turning back in the direction of the jump. This provides a dual benefit: reduced speed acquired by our body by inertia, and, in addition, prevents the danger of falling on his back as Bouncing facing the front side of the body facing in the direction of a possible fall.

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