Situations in which fluid flows at a constant depth are so common that this equation is often also called
Bernoulli’s principle , which is simply Bernoulli’s equation for fluids at constant depth. (Note again that this applies to a small volume of fluid as we follow it along its path.) Bernoulli’s principle reinforces the fact that pressure drops as speed increases in a moving fluid: If
${v}_{2}$ is greater than
${v}_{1}$ in the equation, then
${p}_{2}$ must be less than
${p}_{1}$ for the equality to hold.
Calculating pressure
In
[link] , we found that the speed of water in a hose increased from 1.96 m/s to 25.5 m/s going from the hose to the nozzle. Calculate the pressure in the hose, given that the absolute pressure in the nozzle is
$1.01\phantom{\rule{0.2em}{0ex}}\times \phantom{\rule{0.2em}{0ex}}{10}^{5}\phantom{\rule{0.2em}{0ex}}{\text{N/m}}^{2}$ (atmospheric, as it must be) and assuming level, frictionless flow.
Strategy
Level flow means constant depth, so Bernoulli’s principle applies. We use the subscript 1 for values in the hose and 2 for those in the nozzle. We are thus asked to find
${p1}_{}$ .
Solution
Solving Bernoulli’s principle for
${p}_{1}$ yields
This absolute pressure in the hose is greater than in the nozzle, as expected, since
v is greater in the nozzle. The pressure
${p}_{2}$ in the nozzle must be atmospheric, because the water emerges into the atmosphere without other changes in conditions.
Many devices and situations occur in which fluid flows at a constant height and thus can be analyzed with Bernoulli’s principle.
Entrainment
People have long put the Bernoulli principle to work by using reduced pressure in high-velocity fluids to move things about. With a higher pressure on the outside, the high-velocity fluid forces other fluids into the stream. This process is called
entrainment . Entrainment devices have been in use since ancient times as pumps to raise water to small heights, as is necessary for draining swamps, fields, or other low-lying areas. Some other devices that use the concept of entrainment are shown in
[link] .
Velocity measurement
[link] shows two devices that apply Bernoulli’s principle to measure fluid velocity. The manometer in part (a) is connected to two tubes that are small enough not to appreciably disturb the flow. The tube facing the oncoming fluid creates a dead spot having zero velocity (
${v}_{1}=0$ ) in front of it, while fluid passing the other tube has velocity
${v}_{2}$ . This means that Bernoulli’s principle as stated in
If the block is displaced to a position y , the net force becomes Fnet=k(y−y0)−mg=0Fnet=k(y−y0)−mg=0 . But we found that at the equilibrium position, mg=kΔy=ky0−ky1mg=kΔy=ky0−ky1 . Substituting for the weight in the equation yields. Show me an equation of graph.
Is equal to the square of the velocity divided by the radius of circular path of the object
Mukhtaar
how to find maximum acceleration and velocity of simple harmonic motion?
chander
how to find maximum acceleration and velocity of simple harmonic motion and where it occurres?
chander
you can use either motion equations or kinetic equation and potential equation .
lasitha
how destraction 1kg uranium
Sayed
A body of 2.0kg mass makes an elastic collision with another at rest and continues to more in the original direction but with 1/4 of its ori is the mass of the struck body?
I believe because speed is a function of air density, and colder air is more dense
Jerry
At night air is denser because of humidity.
Clifton
Night air is cooler. Sound requires medium to travel so the denser the medium the fastest the sound travels. Humid air is denser then warmer air as in day.
Clifton
The humidity statement is misleading , colder air is more dense period.
Jerry
because there is no any other sound to reverberate with it so it clearly travel to lot of distance
and also humidity
and also due to denser air at night
Azam
please could you guys help me with physics best websites
alpha discoved by Rutherford in 1899 have + charge and similarly to helium nucleus . When give 2 electron it change to helium nuclear( alpha + 2e = he
Sayed
bita has(-) charge it was also discovered by Ratherforth in 1899 (Bi = bita + po +gamma)
Sayed
Gamma is used to strength nuclear and out sametime with alpha and bita velocity 300000km/he discovered Biryquory in 1900 and more power influence then alpha and bita
he was born 1643 in Lancashire England he discovered that white light in fact made of all color in rainbow and discovered gravity force and pass aye in 1727
Sayed
he was born 1643 in Lancashire England he discovered that white light in fact made of all color in rainbow and discovered gravity force and pass aye in 1727