Fluids

  1. What is the pressure exerted by an 65kg person standing on the ground with shoes that are each 50cm² in area?  How about if she stands on one foot?  How about if she is wearing high heels that have a surface contact area of 10cm²?
  2. How much force does one atmosphere of pressure (101,000 Pa) apply on a 2.5m² surface?
  3. What is the pressure difference between the top an bottom of Lake Tahoe (depth of 501m)?
  4. If the atmosphere a had constant density of 1.2 kg/m³ ,  how much less pressure would there be at 1500m above sea level?
  5. If you release a ballon underwater that has a mass of 0.5kg and is a sphere 10cm in radius, how fast will it accelerate up?
  6. How much force does it take to lift a gold sphere (8cm in diameter) which has a density of 19.3g/cm³ if the sphere is underwater?
  7. A kayak has a mass of 25kg and a volume 0.50m³.  What fraction of the kayak will be submerged if it is floating on water?  How about if a 75kg person sits in the kayak?
  8. If you replace your shower head that has 10 holes each 1.0mm² in size with a new shower head that has 30 holes each 0.1mm² in size how many times faster will the water come out with the new shower head?
  9. A building has a water system where water enters the building from the ground through a 16cm diameter pipe at a velocity of 0.2m/s. It then comes out a 2cm diameter faucet on the fifth floor 18m above. What velocity will the water have when it comes out of the faucet? If the pressure on the water when it enters the building is 700kPa what will the pressure be when it exists the faucet?
  10. If a sail boat has a mass of 15000kg and a sail that is 30m² in area how much faster must air pass in front of the sail compared to behind it for the boat to accelerate at 2.0 m/s²?
  11. Sometimes during tornados the roofs of houses can be pulled off.  If the roof of a house is 25m² in area and has a mass of 4500kg and only the force of gravity keeps it attached, how fast would the wind have to be blowing for the roof to be lifted off of this house? Note that the air below the roof is not moving.