11. High fluid pressure provides a buoyancy force upwards on the glacier, reducing the friction at its base. 12. This provides a buoyancy force , " lifting " the glacier from the bed and reducing the friction force. 13. Buoyancy force is based on the basic principle of pressure variation with depth, since pressure increases with depth.14. Marine birds also tend to have higher than expected body mass as a mechanism to counteract buoyancy forces when submerged. 15. From the Archimedes buoyancy principle, the buoyancy force acting on the hydrometer is equal to the weight of liquid displaced. 16. Hence buoyancy force arises as pressure on the bottom surface of the immersed object is greater than that at the top. 17. The injected bubbles / droplets are typically of a lower density than the coolant and thus experience an upward buoyancy force . 18. The subducting slab undergoes backward sinking due to the negative buoyancy forces causing a retrogradation of the trench hinge along the surface. 19. The buoyancy force exerted on a body can now be calculated easily, since the internal pressure of the fluid is known. 20. While it remains submerged buoyancy forces cancel the weight of the trapped water and the weight of the tube is effectively zero.
