Kinematics

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Škola Gymnázium, Brno, Slovanské
námestí 7 Šablona III/2 Inovace a zkvalitnení
výuky prostrednictvím ICT Název projektu
Inovace výuky na GSN prostrednictvím ICT Císlo
projektu CZ.1.07/1.5.00/34.0940 Autor RNDr.
Bc. Miroslav Hruška Tematická oblast
Gravitational field and motion of bodies
(gravitacní pole a pohyb teles) Název DUMu
Hydrostatics revision Kód VY_32_INOVACE_FY.4.
17 Datum 22. 4. 2014 Cílová skupina Žáci
stredních škol s CLIL výukou fyziky v
anglictine Klícová slova Hydrostatics,
hydrostatic pressure, Pascals law, Archimedes
principle Anotace Prezentace procvicuje
principy Pascalova a Archimedova zákona
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Gravitational field and motion of bodies

• 17. Hydrostatics revision

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Hydrostatics
Which law deals with pressure, and which with
force?
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Fill in the gaps I

• The cause of the . in a fluid can be
• an force acting on the fluid
• the forces of acting on individual ..
  of the fluid
• The pressure by an .. force acting on a
  liquid in a closed is at all . of the
  liquid the same

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Fill in the gaps I solution

• 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
• The pressure caused by an external force acting
  on a liquid in a closed container is at all
  points of the liquid the same

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Exercise I

• 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?
• F1 10 N, r1 2 cm, r2 20 cm
• F2 ?

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Solution I

• The area of the small piston is
• S1 p 22 cm2
• The area of the large piston is
• S2 p 202 cm2
• The force acting on the large piston is
• N

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Fill in the gaps II

• 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

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Fill in the gaps II solution

• 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

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Exercise II

• Find the hydrostatic pressure in water at a depth
  of 5 m.
• h 5 m, ? 1000 kg/m3, g 10 m/s
• ph ?
• ph h?g 5 1000 10 Pa 50 kPa
• The hydrostatic pressure is 50 kPa.

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Exercise III

• Find the net force actingon an iron cube of
  volume 100 cm3 completely immersed in water (?t
  7860 kg/m3).
• The buoyant force Fvz
• The force of gravity FG

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Solution III

• V 100 cm3 0.0001 m3
• ?T 7860 kg/m3
• g 10 m/s2
• ?k 1000 kg/m3
• The buoyant force Fvz
• The force of gravity FG

Since ?T gt ?k , F FG Fvz 7.86 N 1.00 N
6.86 N
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That is all for now

• Thank you for your attention

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• Materiál je urcen pro bezplatné používání pro
  potreby výuky a vzdelávání na všech typech škol a
  školských zarízeních. Jakékoliv další využití
  podléhá autorskému zákonu.
• Zdroje
• Bednarík, 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 Learners
  Dictionary of Current English. 5. vyd. Oxford
  Oxford University Press, 1995. 1428 s. ISBN
  0-19-431423-5