![]() Water pressure inside a hose nozzle can be less than atmospheric pressure due to the Bernoulli effect. Water emerges from two leaks in an old boot.Ģ1. To what maximum height can the water squirt from Leak 1? How does the velocity of water emerging from Leak 2 differ from that of leak 1? Explain your responses in terms of energy. The old rubber boot shown in Figure has two leaks. Explain where the force comes from in terms of energy.Ģ0. Why? When you put your hand in front of the emerging stream you feel a force, yet the water’s gauge pressure is zero. Water that has emerged from a hose into the atmosphere has a gauge pressure of zero. Based on Bernoulli’s equation, what are three forms of energy in a fluid? (Note that these forms are conservative, unlike heat transfer and other dissipative forms not included in Bernoulli’s equation.)ġ9. Why does this happen?ġ2.3: The Most General Applications of Bernoulli’s Equationġ8. If you lower the window on a car while moving, an empty plastic bag can sometimes fly out the window. (Figure.) How does the fluid rise up in the vertical tube in the bottle?Ītomizer: perfume bottle with tube to carry perfume up through the bottle. A perfume bottle or atomizer sprays a fluid that is in the bottle. Explain in terms of energy how the water can emerge from the nozzle against the opposing atmospheric pressure.ġ6. Explain why atmospheric pressure would push you toward the moving train.ġ5. It is dangerous to stand close to railroad tracks when a rapidly moving commuter train passes. ![]() Use Bernoulli’s principle to explain these phenomena.ġ4. Roofs are sometimes pushed off vertically during a tropical cyclone, and buildings sometimes explode outward when hit by a tornado. Why is it preferable for airplanes to take off into the wind rather than with the wind?ġ2. Is there a limit to the height to which an entrainment device can raise a fluid? Explain your answer.ġ1. Explain how this works in terms of Bernoulli’s principle.ġ0. Some chimney pipes have a T-shape, with a crosspiece on top that helps draw up gases whenever there is even a slight breeze. These are very commonly used in carburetors and aspirators.ĩ. How does this bolster entrainment?Ī tube with a narrow segment designed to enhance entrainment is called a Venturi. Many entrainment devices have a constriction, called a Venturi, such as shown in Figure. ![]() Give an example of entrainment not mentioned in the text.Ĩ. Why is \(\displaystyle P_o\) less than atmospheric? Why is \(\displaystyle P_o\) greater than \(\displaystyle P_i\)?ħ. Explain why, and discuss whether surface tension enhances or reduces the effect in each case.Ħ. Conversely, a stream of water falling straight down from a faucet narrows. Water is shot nearly vertically upward in a decorative fountain and the stream is observed to broaden as it rises. You can squirt water a considerably greater distance by placing your thumb over the end of a garden hose and then releasing, than by leaving it completely uncovered. ![]()
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