Upthrust

• Upthrust definition

  The resultant upward force of 2 forces of the water
• Upthrust

  1. An object that is partly, or completely, submerged experiences a greater pressure on its bottom surface than on its top surface

  2. This causes a resultant force upwards

  3. Upwards force exerted by a liquid or gas on an object floating in it

  4. The upthrust force is equal in size to the weight of the fluid displaced by the object
• Pressure

  Helps blood to move around the body and allows organisms to breathe
• Every living thing on Earth is in balance with the pressure of the air or water around it
• The unit of thrust is the Newton (N) or the kilogram force (kgf), gram force (gf)
• Thrust

  The unit of thrust is the Newton (N) or the kilogram force (kgf), gram force (gf)
• Pressure

  Helps blood to move around the body and allows organisms to breathe
• Upthrust units

  1 kgf = 1000 gf; 1 kgf = 10 N; 1 N = 100 gf
• Every living thing on Earth is in balance with the pressure of the air or water around it
• Floating and sinking

  1. If the upthrust is less than the weight of the object, the object will sink
  2. If the density of the object is greater than the density of the fluid, the object can never displace enough fluid to create an upthrust that will hold its weight up so it sinks
  3. The sinking only stops when the object reaches the bottom and an extra reaction force is added to the upthrust in order to balance the weight
  4. If the upthrust is larger than the weight of the object, the object will rise
• When you jump into a swimming pool

  You rise back up to the surface because the upthrust is more than your weight, creating a resultant upwards force