Presentation on theme: "Liquid and Atmospheric"— Presentation transcript:
1 Liquid and Atmospheric - Pressure -Liquid and AtmosphericPressurePressure MeasurementDefinition of Pressureby Rifki Irawan & Fiqri Hakim
2 Pressure F (N) force P (Pa) = Pressure = A (m2) area Definition of PressurePressureis the force acting normallyor perpendiculary per unit areaF (N)forceP (Pa) =Pressure =A (m2)areaSI unit for Pressure is Pascal (Pa) = 1 N m-2
3 “ same force, different area, different pressure “ Weight = 100 NArea = 0.01 m2Pressure = 10,000 PaWeight = 100 NArea = 0.1 m2Pressure = 1000 Pa“ same force, different area, different pressure “
4 Force = pressure x area = 100 Pa x 6 m2 = 600 N Example 1.The wind pressure on the wall is 100 Pa. If the wall has an area of 6 m2, what is the force exert on it?To solve this problem, you need to rearrange the pressure equation:Force = pressure x area= 100 Pa x 6 m2= 600 N
5 Area = 0.5 m x 1.0 m F = mass x gravitasi Pressure = force/area Example 2.A concrete block has a mass of 2,600 kg. If the block measures 0.5 m length by 1.0 m width and 2.0 m height, what is the maximum pressure of the concrete block that can exert when resting on the ground?(g = 10 m · s-2)Area = 0.5 m x 1.0 m= 0.5 m2F = mass x gravitasi= 2,600 kg x 10 m · s-2= 26,000 NPressure = force/area= 26,000 N / 0.5 m2= 52,000 Pa
6 Liquid and Atmospheric Pressure “A liquid exerts pressure because of its weight”Pressure acts in all directionPressure increases with depthPressure depends on the density of the liquidPressure does not depend on the shape of the container
7 Volume liquid = base area x depth = A x h Weight= mass x gravitymass liquid = density x volume = x A x h“pressure of the liquid depends on the density of the liquid itself”Weight liquid = mass liquid x gravity = x A x h x gmassDensity =Weight liquid = Force of the liquid = A h gvolumeForce liquid A h gPressure liquid =Area containerAPressure liquid = h g
8 Pressure = ρhg = 1,000 kg/m3 x 2 m x 10 N/kg = 20,000 Pa Example 1. If the density of water is kg/m3, what is the pressure due to the water at the bottom of a swimming pool 2 m deep?First, define the data which givenDensity= kg/m3Height= 2 mGravity= 10 N/kgPressure = ρhg= 1,000 kg/m3 x 2 m x 10 N/kg= 20,000 Pa
9 Atmospheric pressureThe athmosphere is a deep ocean of air which surround the earth. In some ways, it is like liquid:Its pressure acts in all directions.Its pressure becomes less as you rise up through itUnlike a liquid, air can be compressed.
10 Atmospheric pressureThe pressure that will support a column of mercury mm hight is known as standard atmospheric pressure or 1 atmosphere (1 atm)1 atm = PaIn weather forecasting we often used milibar (mb)1 mb = 100 Pa
11 The instruments The mercury barometer Atmospheric press the mercury up the tube because the space at the top of the tube has no air in it.mm Hg = 1 atm
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