Chapter 7 Pressure

Pressure

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• Bildunterschrift: Oh My God What Is This?!

What is Pressure?

• Pressure is DEFINED as the FORCE ACTING per UNIT AREA.
• SI unit of pressure: Newton per sq metre/pascal
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• Bildunterschrift: p= pressure in (Pa), F= force in (N), A= area in metre sq.

Pressure in liquids

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• The amount of pressure inside a body of liquid increases with depth.
• At greater depths,the weight of liquid is greater.Hence,the pressure is greater.
• Liquid pressure formula:
• p= height(m) x Density of liquid x gravitational field strength

What affects the pressure in liquids?

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• Pressure in liquid depends only on the vertical height of the liquid column and the,not the volume & the cross-sectional area/shape of the column.
• Hence,at equilibrium,the liquid level in all the columns is at the same height.

Transmission of pressure in liquids

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• Bildunterschrift: Hydraulic Machine
• We learned hydraulic action in Geography and we're gonna learn about hydraulic machines in Physics..
• Hydraulic machines enable heavy objects like cars to be lifted with a small amount of effort.
• They use liquids to transmit pressure.Pressure is applied to an enclosed liquid,the pressure is transmitted equally to all other parts of the liquid.(Pascal's Principle)

Hydraulic Press