kola ablona Nzev projektu slo projektu Autor Tematick
Škola: Šablona: Název projektu: Číslo projektu: Autor: Tematická oblast: Název DUMu: Kód: Datum: Cílová skupina: Klíčová slova: Anotace: Gymnázium, Brno, Slovanské náměstí 7 III/2 – Inovace a zkvalitnění výuky prostřednictvím ICT Inovace výuky na GSN prostřednictvím ICT CZ. 1. 07/1. 5. 00/34. 0940 RNDr. Bc. Miroslav Hruška Gravitational field and motion of bodies (gravitační pole a pohyb těles) Hydrostatics – revision VY_32_INOVACE_FY. 4. 17 22. 4. 2014 Žáci středních škol s CLIL výukou fyziky v angličtině Hydrostatics, hydrostatic pressure, Pascal’s law, Archimedes’ principle Prezentace procvičuje principy Pascalova a Archimedova zákona 1
Gravitational field and motion of bodies 17. Hydrostatics – revision 2
Hydrostatics Which law deals with pressure, and which with force? 3
Fill in the gaps I 1. 2. 3. The cause of the ……………. in a fluid can be: an ……………… force acting on the fluid the forces of ………… acting on individual ……………. . of the fluid 4. 5. The pressure ………… by an …………. . force acting on a liquid in a closed ……………… is at all ………. of the liquid the same 4
Fill in the gaps I – solution q • • The cause of the pressure in a fluid can be: an external force acting on the fluid the forces of gravity acting on individual particles of the fluid • q The pressure caused by an external force acting on a liquid in a closed container is at all points of the liquid the same 5
Exercise I q A force of 10 N acts on the small piston of a hydraulic device of radius 2 cm. The large piston has got a radius of 20 cm. Find the magnitude of the force acting on the large piston? F 1 = 10 N, r 1 = 2 cm, r 2 = 20 cm q F 2 = ? q 6
Solution I The area of the small piston is S 1 = π × 22 cm 2 q The area of the large piston is S 2 = π × 202 cm 2 q The force acting on the large piston is q N 7
Fill in the gaps II q q We refer to the …………… caused by the forces of …………… acting on individual particles of a liquid as the ……………… pressure Any object ………………. in a liquid is …………… up by a force equal to the ………… of the liquid …………… by the object 8
Fill in the gaps II – solution q q We refer to the pressure caused by the forces of gravity acting on individual particles of a liquid as the hydrostatic pressure Any object immersed in a liquid is buoyed up by a force equal to the weight of the liquid displaced by the object 9
Exercise II q Find the hydrostatic pressure in water at a depth of 5 m. h = 5 m, ρ = 1000 kg/m 3, g = 10 m/s q ph = ? q ph = hρg = 5 × 1000 × 10 Pa = 50 k. Pa q The hydrostatic pressure is 50 k. Pa. 10
Exercise III q q q Find the net force acting on an iron cube of volume 100 cm 3 completely immersed in water (ρt = 7860 kg/m 3). The buoyant force Fvz The force of gravity FG 11
Solution III q q q V = 100 cm 3 = 0. 0001 m 3 ρT = 7860 kg/m 3 g = 10 m/s 2 ρk = 1000 kg/m 3 The buoyant force Fvz The force of gravity FG Since ρT > ρk , F = FG – Fvz = 7. 86 N – 1. 00 N = 6. 86 N 12
That is all for now Thank you for your attention 13
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 14
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