Upthrust

    Cards (9)

    • When an object is submerged in a liquid, there is a greater height of liquid above the bottom surface than above the top surface - The bottom surface experiences a greater pressure than the top surface and this creates a resultant force upwards
    • What is upthrust?
      The upwards force exerted by a fluid on a submerged object
    • When does an object float?
      When its weight is equal to the upthrust
    • When does an object sink?
      When its weight is greater than the uprthrust
    • The density of an object indicates if it will float or sink
    • An object less dense than the liquid : displaces a volume of liquid greater than its own weight so that it will rise to the surface - will float with some of the remaining below the surface - displaces liquid of equal weight to the object
    • What happens if an object has a low density?
      More of the object will remain above the surface
    • What happens to an object denser than the surrounding liquid?
      It cannot displace enough liquid equal to its own weight so it sinks
    • The size of the upthrust is equal to the weight of the liquid displaced (by the object) - no matter how dense an object is