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• what equation can be used to calculate the pressure due to a column of liquid?

  pressure = height of the column x density of the liquid x gravitational field strength
• why, in a liquid, pressure at a point increases with the height of the column of liquid above that point

  • as the depth increases, the number of particles above that point increases
  • the weight of these particles adds to the pressure at that point
  • liquid pressure increases w depth
• why does pressure in liquid increase with density?

  • density is a measure of the compactness of a substance
  • the more dense a liquid is, the more particles it has in a given volume
  • there are more collisions with particles
  • pressure is higher
• what is upthrust?

  • when an object is submerged in a fluid, the pressure of the fluid exerts a force on it from every direction
  • since pressure increases w depth, the force exerted on the bottom surface is larger than on the top surface
  • this creates a resultant force upwards - upthrust
• what factors influence if an object floats or sinks?

  • if upthrust on an object is equal to object's weight, the forces balance and the object floats
  • if an object's weight is more than the upthrust, the object sinks
  • whether an object floats of not depends on its density