fluids

• What is meant by the term ‘fluid’?

  A liquid or a gas.
• At what angle do the forces due to pressure act on a given surface in a fluid?

  At right angles (normal to) the surface.
• What is the equation used to calculate pressure?

  Pressure (Pa) = Force (N) / Area (m²)
• Why does atmospheric pressure vary with height above the earth's surface?

  The number of air molecules decreases the higher you go , this means the weight of air above a set point decreases , also decreasing pressure
• True or False? The pressure in a fluid is determined by the fluid and the atmospheric pressure.

  True
• In what direction does pressure act in a fluid?

  All directions.
• How does pressure in fluids increase with depth?

  As depth increases, mass of liquid above the point increases , this means that the force produced by that mass also increases , since the force has increased while the area has remained constant , the pressure will increase
• Why does pressure in fluids increase with density?

  More particles in a volume increase weight.
• What equation shows the magnitude of pressure in liquids at different depths?

  Pressure (Pa) = Column height (m) x density (kg/m³) x gravitational field strength (N/kg)
• Why are objects in a fluid subject to an upthrust?

  Higher pressure below than above the object.
• What is the magnitude of the upthrust felt by an object?

  Equal to the weight of fluid displaced.
• How can you determine if an object will sink or float?

  If upthrust > weight, it will float.
• Why would an object with a density more than that of water never float?

  Not enough volume displaced for upthrust.