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/ 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: 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.

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

3  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) Complete I

4  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) Complete II

5  We know that frames of reference where Newton’s laws are not valid are called non-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 almost inertial (differences can appear and be very important in some cases) Non-inertial frames of reference

Zdroj: archiv autora6 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 autora7  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) Observer on the Earth's surface

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 F s 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 2 nd law is then  Inertial force has no force of reaction! resultant force of real forces fictitious inertial force acceleration of an object

11  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? Revision

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

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, s. ISBN  Hornby, A. S. Oxford Advanced Learner’s Dictionary of Current English. 5. vyd. Oxford: Oxford University Press, s. ISBN