Bernoulli’s Equation represents· a tube through which an ideal fluid is flowing at a steady rate. In a time interval At, suppose that a volume of fluid ·AV, colored purple in, enters the tube at the left (or input) end and an identical volume, colored green in emerges at the right (or output) end. The emerging […]
The Equation Of Continuity You may have noticed that you can increase the speed of the water emerging from a garden hose by partially closing the hose opening with your dhurrie. Apparently the speed of the water depends on the cross-sectional area A through which the’ water flows. Here we wish to derive an expression that relates ” and […]
Ideal fluids in Motion The motion of real fluids is very complicated and not yet fully understood. Instead, we shall discuss the motion of an ideal fluid, which is simpler to handle mathematically and yet provides useful results. Here are four assumptions that we make about our ideal fluid; they all are concerned with few: 1. […]
Archimedes’ Principle Figure 15-9 shows a student in a swimming pool, manipulating a very thin plastic sack (of negligible mass) that is filled with water. She finds that the sack and its contained water are in static equilibrium. tending neither to rise nor to sink. The downward gravitational force F.. on the contained water must be balanced by […]
Pascal’s Principle and the Hydraulic Lever shows how Pascal’s principle can be made the basis of a hydraulic lever. In operation, let an external force of magnitude F, be directed downward on the lefthand (or input) piston, whose area is Aj. An incompressible liquid in the device then produces an upward force of magnitude F; on the righthand […]
Pascal’s Principle When you squeeze one end of a tube to get toothpaste out the other end, you are watching Pascal’s principle in action. This principle is also the basis for theHeimlich maneuver, in which a sharp pressure increase properly applied to the abdomen is transmitted to the throat, forcefully ejecting food lodged there. The principle was […]
Measuring Pressure The Mercury Barometer Figure J5-5a shows a very basic mercury barometer, a device used to measure the pressure of the atmosphere. The long glass tube is filled with mercury and inverted with its open end in a dish of mercury, as the figure shows. The space above the mercury column contains only mercury vapor, […]
fluids at Rest Figure I5-2a shows a tank of water-or other liquid-open to the atmosphere. As every diver knows, the pressure increases with depth below the air- water interface.The diver’s depth gauge. in fact. a pressure sensor much like that of Fig. 15-1 h. As every mountaineer knows. the pressure decreases with altitude as one […]
Density and Pressure When we discuss rigid bodies, we are concerned with particular lumps of matter, such as wooden blocks, baseballs, or metal rods. Physical quantities that we find useful, and in whose terms we express Newton’s laws, are I1.7aSS and force. We might speak, for example, of a 3.6 kg block acted on by a 25 N […]
What Is a Fluid? A fluid, in contrast to a solid, is a substance that can flow. Fluids conform to the boundaries of any container in which we put them. They do so because a fluid cannot sustain a force that is tangential to its surface. (In the more formal language of ‘Section 13-6, a fluid is a […]