19. Fluid Mechanics

Density

Open Question
The 30-cm-long left coronary artery is 4.6 mm in diameter. Blood pressure drops by 3.0 mm of mercury over this distance. What are the (a) average blood speed and (b) volume flow rate in L/min through this artery?
Open Question
Two pulses are moving in opposite directions at 1.0 cm/s on a taut string, as shown in Fig. E15.34. Each square is 1.0 cm.
Sketch the shape of the string at the end of (a) 6.0 s.
Multiple Choice
A wooden door is 1 m wide, 2.5 m tall, 6 cm thick, and weighs 400 N. What is the density of the wood in g/cm³? (use g = 10 m/s²)
Multiple Choice
Suppose an 80 kg (176 lb) person has 5.5 L of blood (1,060 kg/m³ ) in their body. How much of this person's total mass consists of blood? What percentage of the person's total mass is blood?
Multiple Choice
You want to verify if a 70-g crown is in fact made of pure gold (19.32 g/cm³ ), so you lower it by a string into a deep bucket of water that is filled to the top. When the crown is completely submerged, you measure that 3.62 mL of water has overflown. Is the crown made of pure gold?
Multiple Choice
You have three objects in front of you. Object A has a volume of $4 {cm}^{3}$ . object B has a volume of $7 {cm}^{3}$ . and object C has a volume of $10 {cm}^{3}$ . They all have the same mass. What is the correct ranking of the objects from most dense to least dense?
Multiple Choice
Suppose a cubic box contains so much air at $0 ℃$ that the mass of the air inside is equal to the mass of $1 . 0 L$ of water. What would be the side length of such a box?
Multiple Choice
Different materials in the body have different densities, and therefore will tend to make a person float or sink to different extents. Which bodily material is most buoyant (helps you stay afloat the most)?
Open Question
A brass wire is to withstand a tensile force of 350 N without breaking. What minimum diameter must the wire have?
Open Question
A square steel plate is 10.0 cm on a side and 0.500 cm thick. (a) Find the shear strain that results if a force of magnitude 9.0×10^5 N is applied to each of the four sides, parallel to the side. (b) Find the displacement x (in centimeters).
Open Question
In the Challenger Deep of the Marianas Trench, the depth of seawater is 10.9 km and the pressure is 1.16×10^8 Pa (about 1.15×10^3 atm). (a) If a cubic meter of water is taken from the surface to this depth, what is the change in its volume? (Normal atmospheric pressure is about 1.0×10^5 Pa. Assume that k for seawater is the same as the freshwater value given in Table 11.2.)
Open Question
A specimen of oil having an initial volume of 600 cm3 is subjected to a pressure increase of 3.6×10^6 Pa, and the volume is found to decrease by 0.45 cm^3. What is the bulk modulus of the material and the compressibility?
Open Question
A solid gold bar is pulled up from the hold of the sunken RMS Titanic. (c) The bulk modulus of lead is one-fourth that of gold. Find the ratio of the volume change of a solid lead bar to that of a gold bar of equal volume for the same pressure change.
Open Question
Stress on a Mountaineer's Rope. A nylon rope used by mountaineers elongates 1.10 m under the weight of a 65.0-kg climber. If the rope is 45.0 m in length and 7.0 mm in diameter, what is Young's modulus for nylon?
Open Question
A circular steel wire 2.00 m long must stretch no more than 0.25 cm when a tensile force of 700 N is applied to each end of the wire. What minimum diameter is required for the wire?