# Shared Flashcard Set

## Details

IGCSE Physics Section 4 (a) and 4(b)
Pressure and Simple Kinetic Molecular Model
6
Physics
06/17/2017

Term
 Pressure [image]
Definition
 It is defined as force per unit area It is measured in SI units of Pascal (Pa)   [image]
Term
 Barometer [image]
Definition
 To measure atmospheric pressure an instrument called a Barometer is used. Standard atmospheric pressure is 100 000 Pascal and this will cause the column of Mercury (Hg) to rise up the evacuated tube by 760 mm.   In other words: 100 kPa = 760 mmHg = 1 atmosphere
Term
 How pressure of a gas results from the kinetic energy of particles [image]
Definition
 Gas particles move about quickly and randomly They collide elastically with the walls of the container and change their momentum each time they collide. This change of momentum per unit time imparts a force Many particles exert a total force on each unit area of the container walls In this way pressure is exerted by the sum of the many particle collisions
Term
 Pressure in a liquid [image]
Definition
 The pressure in a liquid depends upon: the density of the liquid the acceleration due to gravity the height of water above the level being considered These three factors go together to produce the equation:   p = ρgh               p=pressure                           ρ=density                           g=acceleration due to gravity                           h=height of water above
Term
 Manometer [image]
Definition
 An instrument used to measure the difference in pressure between two fluids [image]
Term
 How can pressure be used to transmit and magnify force?    [image]
Definition
 Since the liquid is in-compressible (no volume change) the pressure exerted by the first piston is transmitted directly to the second piston In other words pushing piston 1 down will push piston 2 up As this pressure remains constant the ratio of F1/A1 is equal to the ratio of F2/A2 If A2 = 50xA1 then a force of 1 Newton at F1 will produce a 50 Newton force at F2
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