Buoyancy Revisited

1
Buoyancy Revisited
2
Review Questions

• What is Archimedes Principle?
• Buoyant force the weight of the displaced fluid
• What causes a buoyant force?
• Unbalanced pressure there is more pressure
  (force per unit area) acting on the bottom of an
  object submerged in a liquid than on the top
  (Pliq pgh pressure varies directly with
  depth)

3
Buoyancy in a Liquid

• Hannah and her friends go fishing in her 1.20 m3
  rowboat, which has a mass of 100. kg. How many
  60.0 kg people can get into the boat before it
  sinks?

4
Is there buoyancy in air?

• Does air have weight?
• Find the weight of the air in a room with
  dimensions of 8 m x 4.5 m x 6 m. The density of
  air at sea level is 1.30 kg/m3.
• Does air provide a buoyant force?
• A balloon weighing 80 kg has a capacity of 1200
  m3. If it is filled with helium, how great a
  payload can it support? The density of helium is
  0.18 kg/ m3 and the density of air is 1.30 kg/
  m3. Express your answer in Newtons.
• Gas Video Review