Škola: Gymnázium, Brno, Slovanské náměstí 7

1. Škola: Gymnázium, Brno, Slovanské náměstí 7 Šablona: III/2 – Inovace a zkvalitnění výuky prostřednictvím ICT Název projektu: Inovace výuky na GSN prostřednictvím ICT Číslo projektu: CZ.1.07/1.5.00/34.0940 Autor: RNDr. Bc. Miroslav Hruška Tematická oblast: Dynamics of particles (dynamika hmotných bodů) Název DUMu: Non-inertial frames of reference. Inertial forces Kód: VY_32_INOVACE_FY.3.10 Datum: 30. 10. 2013 Cílová skupina: Žáci středních škol s CLIL výukou fyziky v angličtině Klíčová slova: Non-inertial frame of reference, inertial forces Anotace: Prezentace slouží k zavedení pojmu setrvačná síla v neinerciálních vztažných soustavách. Je vhodné ji použít při probírání nového učiva. Na začátku se opakuje předchozí učivo.

2. Dynamics of particles 10. Non-inertial frames of reference. Inertial forces

3. Complete I Galilean principle of …………is a………… of the physical equality of …………frames of ………… in classical …………, which is manifested in the fact that the ……… of mechanics are ………… in all such reference ……… (relativity, principle, inertial, reference, mechanics, laws, identical, frames)

4. Complete II It is ……….. to determine by any mechanical ……… conducted in any ………frame of reference whether the given ……… of reference is at ……… or moving uniformly and rectilinearly (impossible, experiment, inertial, frame, rest)

5. Non-inertial frames of reference We know that frames of reference where Newton’s laws are not valid are callednon-inertial A train speeding up, a tram slowing down, a car turning a curve, … We know that the Earth, as a frame of reference, is almostinertial (differences can appear and be very important in some cases)

6. Non-inertial frames of reference • While a bus is slowing down, a free object in it is accelerating forwards… • … although forces acting on the object are balanced! Zdroj: archiv autora

7. Observer on the Earth's surface  From the point of view of the Earth, the object, thanks to its inertia, just continues moving uniformly in a straight line… (unless acted on by a force) Zdroj: archiv autora

8. Inertial force • From the point of view of the inertial reference frame, everything is correct, according to Newton’s laws • In the non-inertial reference frame, Newton’s laws are not valid… • It seems as if there is another force in non-inertial reference frames… • We refer to it as the inertial force

9. Inertial force (setrvačná síla) • Inertial force is also called a fictitious (fiktivní) force, pseudo force or phantom force • The force Fs does not arise from any physical interaction between two objects, but rather from the acceleration a* of the non-inertial reference frame itself • Formula:

10. Inertial force in Newton’s laws • Newton’s first and second laws get valid also for non-inertial reference frames if we include inertial forces! • Newton’s 2nd law is then • Inertial force has no force of reaction! acceleration of an object resultant force of real forces fictitious inertial force

11. Revision In which frames of reference does inertial force arise? What is a formula for the inertial force? Which Newton’s laws are valid, and which not, in a non-inertial frame of reference if we include inertial force?

12. Revision – answers • In non-inertial reference frames • First and second laws are valid, third is not

13. That is all for now Thank you for your attention

14. Materiál je určen pro bezplatné používání pro potřeby výuky a vzdělávání na všech typech škol a školských zařízeních. Jakékoliv další využití podléhá autorskému zákonu. Zdroje: • Bednařík, M., Široká, M. Fyzika pro gymnázia, Mechanika. Dotisk 3. vyd. Praha: Prometheus, 2004. 288 s. ISBN 80-7196-176-0 • Hornby, A. S. Oxford Advanced Learner’s Dictionary of Current English. 5. vyd. Oxford: Oxford University Press, 1995. 1428 s. ISBN 0-19-431423-5