what is pressure and velocity is ther any relation give me one example?

Answer 1

Pressure is force per unit area, such as pounds per square inch or newton per square meter.

(Example: your car tire might have 32psi air inside of it)

Velocity is change in distance per unit time, such as miles per hour, or feet per second.

(Example: the speed limit is 65 miles per hour)

There is no relation between pressure and velocity...except that your car probably won't travel as fast on flat tires! Pressure (by itself) has nothing to do with speed.

(Edit: Yes, getting into Bernoulli's theorem you can tie pressure and velocity together, in the context of pressure heads, potential head, velocity, friction, head loss, etc. But the asker is asking what is pressure and what is velocity. Seems to me to be a very basic question. How about pressures exerted by the solar wind on a sail, and the resultant velocity after a given time? This, too, is about a relation between pressure and velocity, but I seriously doubt the asker is wanting to know about such complex physics when the question posed is "what is pressure and velocity". I stand by my original answer, given that no context provided by the asker. Perhaps additional information is available?)

Answer 2

There IS a relation between pressure and velocity!

In steady frictionless incompressible flow, the Bernoulli equation can be expressed as v^2/2 + P/rho + g*z = constant
along any streamline.
v is velocity
P is pressure
rho is density
g is gravity
z is height (so a horizontal flow can eliminate that part of the equation

Basically pressure is proportional to the square of velocity.
There are many ways to rewrite the equation to make it conveneint for different cases

Answer 3

p/r + ½v2 + gz = constant

where p, r, v, g, and z are the fluid pressure, the fluid density, the speed of the fluid, the acceleration of gravity, and the height, measured from some arbitrary reference point.

Bermoulli's equation

Answer 4

They are inversely proportional. For eg. in polycythemia- increased RBCs viscosity is more, velocity is less but BP is uncreased and in anemia- decreased RBCs, viscosity is less, velocity is more, BP is decreased.