pressure and pressure differences

    Cards (12)

    • a fluid can either be a liquid or gas
    • if pressure acts on a bigger area is will produce a larger force
    • the atmosphere is a relatively thin layer of air around the earth
    • the greater the altitude the less dense the atmosphere and the lower the atmospheric pressure
    • at a high altitude there is less air above a surface than at lower altitude so there is a smaller weight of air acting on the surface
    • pressure in a column of liquid depends on
      • the height of the column above the point
      • the density of the liquid
    • the higher the column the more dense the liquid
      • the greater weight above the point
      • the greater force on the surface at that point
      • the greater the pressure
    • pressure of a liquid depends on the depth
    • for an object to float , the upthrust must be equal to the objects weight
    • if the upthrust is less than the objects weight it sinks
    • size of the upthrust is the same as the weight of the water displaced
    • if an bject can displace its own weight of water , then the upthrust will be equal to the objects weight and float
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