When a fluid, such as air or water, flows past a solid object, the motion of the fluid creates a difference in pressure on opposite sides of the object. This pressure difference results in a net upward force, which is known as friction upthrust.
Friction upthrust is caused by the friction between the fluid and the surface of the object. As the fluid flows past the object, the friction force creates a boundary layer of slow-moving fluid near the surface. This slow-moving fluid exerts a higher pressure on the side of the object facing the oncoming flow compared to the side facing away from the flow.
The difference in pressure between the two sides of the object generates a net upward force, which is the friction upthrust. This force is proportional to the velocity of the fluid, the density of the fluid, the surface area of the object, and the coefficient of friction between the fluid and the surface.
Friction upthrust plays a crucial role in various applications and phenomena, such as the flight of airplanes, the motion of ships, and the rotation of sports balls like soccer balls and tennis balls. It is an essential concept in understanding the behavior of fluids and their interactions with solid objects.
