Viscosity, Drag Force in Urdu / Hindi || 11th Class Physics - Chapter No 06 || viscosity in urdu

Drag Forces
Like friction, the drag force always opposes the motion of an object. Unlike simple friction, the drag force is proportional to some function of the velocity of the object in that fluid. This functionality is complicated and depends upon the shape of the object, its size, its velocity, and the fluid it is in. For most large objects such as cyclists, cars, and baseballs not moving too slowly, the magnitude of the drag force
F
D
is proportional to the square of the speed of the object. We can write this relationship mathematically as
.
When taking into account other factors, this relationship become
where C is the drag coefficient, A is the area of the object facing the fluid, and
ρ
is the density of the fluid. (Recall that density is mass per unit volume.) This equation can also be written in a more generalized fashion
where b is a constant equivalent to

.
We have set the exponent n for these equations as 2 because when an object is moving at high velocity through air, the magnitude of the drag force is proportional to the square of the speed. As we shall see in Fluid Mechanics, for small particles moving at low speeds in a fluid, the exponent n is equal to 1.

Drag Force
Drag force

is proportional to the square of the speed of the object. Mathematically,
,
where C is the drag coefficient, A is the area of the object facing the fluid, and
ρ
is the density of the fluid.

Athletes as well as car designers seek to reduce the drag force to lower their race times ((Figure)). Aerodynamic shaping of an automobile can reduce the drag force and thus increase a car’s gas mileage.

#viscosity #dragforce #fluiddynamics

viscosity in urdu

Видео Viscosity, Drag Force in Urdu / Hindi || 11th Class Physics - Chapter No 06 || viscosity in urdu канала The Base Academy