Page 138 - PowerPoint Presentation

PRIMENA RAZLAGANJA SILA I TRANSFORMACIJA ENERGIJA

APPLIANCE OF RESOLUTION OF A FORCE INTO COMPONENTS AND
TRANSFORMATION OF ENERGIES

Autor: Luka Jevtović Učenik VII razreda OŠ „Ujedinjene nacije“ i polaznik Regionalnog
centra za talente–Beograd II

Mentor: Milan Prokić

Rezime

U svakodnevnom životu neretko nailazimo na postupke ili mašine koji, pre svega, koriste zakone
o razlaganju sila i transformacija potencijalne u kinetičku energiju. Let aviona, padanje predmeta, kretanje
jedrilice samo su neki od primera. To je ono sto će se dokazati u ovom tekstu. Koristeći se samo prostom
algebrom i geometrijom, kao i nekim od zakona fizike (poput Njutnovih zakona) moguće je precizno
objasniti ove postupke. Na primer, padanje predmeta sa neke visine je ravnomerno ubrzano kretanje bez
početne brzine. A koliko smo se samo puta kao mali pitali kako to da avion leti a ne pada. Odgovor se
krije upravo u razlaganju sila. Zahvaljujući odgovarajućem uglu krila i jačine motora, ogromni avion
može savladati gravitacionu silu i odleti od jednog do drugog mesta. Lako je shvatiti kako se jedrilica
kreće kada vetar duva pravo u jedro, ali šta kada duva pod drugim uglom? I na to se može odgovoriti uz
pomoć razlaganja sila. Pomeranjem jedra za određeni ugao u odnosu na pravac vetra, mi kontrolišemo
jedrenjak i postižemo da ide u pravcu kojim mi želimo da ide. Većina eksperimenata koji su nabrojani
gore se mogu obaviti u kućnim, odnosno školskim uslovima.

Ključne reči: razlaganje sila, transformacija energije, kinetička energija, potencijalna energija, gravitacija,
kretanje

Summary

In everyday life, we often come across procedures or machines that, first of all, use resolution of a
force into components and transformation of potential into kinetic energy. Airplane flights, falling of
objects, movements of a sailboat are just some of the examples. That is what is going to be shown in this
text. By using only simple algebra and geometry, as well as some laws of physics (like Newton’s laws) it
is possible to precisely explain these procedures. For example, falling of an object from some height is
motion with constant acceleration without initial speed. And how many times have we asked ourselves as
children how do airplanes fly and don’t fall? The answer is hiding exactly in the resolution of a force into
components. Thanks to the corresponding angle of wings and force of the engine, a giant plane can beat
gravitation force and fly from one location to other. It’s easy to understand how the sailboat moves when
the wind is blowing directly into the sail, but what about when it’s blowing from another angle? We can
answer that question by resolution of a force into components, too. By adjusting the angle of sail to the
direction of wind, we can easily control the sailboat and make it go in the direction we want it to go. Most
of the experiments mentioned above can be done at home or at school.

Key words: resolution of a force into components, transformations of energies, kinetic energy, potential
energy, gravitation, motion