(10%) Problem 2: Nail tips exert tremendous pressures when they are hit by hammers because they exert a large force over a small area. 50% Part (a) What force, in newtons, must be exerted on a nail with a circular tip of a diameter 0.85 mm to create a pressure of 3.05 × 10° N/m²? (This high pressure is possible because the hammer striking the nail is brought to rest in such a short distance.) F=1.73 * 103 F = 1730 v Correct! 50% Part (b) How many people of mass 82 kg would have to stand on this nail to exert this force? Round to the nearest integer.

(10%) Problem 2: Nail tips exert tremendous pressures when they are hit by hammers because they exert a large force over a small area. 50% Part (a) What force, in newtons, must be exerted on a nail with a circular tip of a diameter 0.85 mm to create a pressure of 3.05 × 10° N/m²? (This high pressure is possible because the hammer striking the nail is brought to rest in such a short distance.) F=1.73 * 103 F = 1730 v Correct! 50% Part (b) How many people of mass 82 kg would have to stand on this nail to exert this force? Round to the nearest integer.

University Physics Volume 1

18th Edition

ISBN:9781938168277

Author:William Moebs, Samuel J. Ling, Jeff Sanny

Publisher:William Moebs, Samuel J. Ling, Jeff Sanny

Chapter14: Fluid Mechanics

Section: Chapter Questions

Problem 50P: The tip of a nail exerts tremendous pressure when hit by a hammer because it exerts a large force...

See similar textbooks

Similar questions

A backyard swimming pool with a circular base of diameter 6.00 m is filled to depth 1.50 m. (a) Find the absolute pressure at the bottom of the pool. (b) Two persons with combined mass 150 kg enter the pool and float quietly there. No water overflows. Find the pressure increase at the bottom of the pool after they enter the pool and float.
An airplane is cruising al altitude 10 km. The pressure outside the craft is 0.287 atm; within the passenger compartment, the pressure is 1.00 atm and the temperature is 20C. A small leak occurs in one of the window seals in the passenger compartment. Model the air as an ideal fluid to estimate the speed of the airstream flowing through the leak.
A submarine is stranded on the bottom of the ocean with its hatch 25.0 m below the surface. Calculate the force needed to open the hatch from the inside, given it is circular and 0.450 m in diameter. Air pressure inside the submarine is 1.00 atm.
Two thin-walled drinking glasses having equal base areas but different shapes, with very different cross-sectional areas above the base, are filled to the same level with water. According to the expression P = P0 + gh, the pressure is the same at the bottom of both glasses. In view of this equality, why does one weigh more than the other?
A fire hose has an inside diameter of 6.40 cm. Suppose such a hose caries a flow of 40.0 L/s starting at a gauge pressure of 1.62106 N/m2. The hose goes 10.0 m up a ladder to a nozzle having an inside diameter of 3.00 cm. Calculate the Reynolds numbers for flow in the fire hose and nozzle to show that flow in each must be turbulent.
The human brain and spinal cord are immersed in the cerebrospinal fluid. The fluid is normally continuous between the cranial and spinal cavities and exerts a pressure of 100 to 200 mm of H2O above the prevailing atmospheric pressure. In medical work, pressures are often measured in units of mm of H2O because body fluids, including the cerebrospinal fluid, typically have nearly the same density as water. The pressure of the cerebrospinal fluid can be measured by means of a spinal tap. A hollow tube is inserted into the spinal column, and the height lo which the fluid rises is observed, as shown in Figure P9.83. If the fluid ruses to a height of 160. mm, we write its gauge pressure as 160. mm H2O. (a) Express this pressure in pascals, in atmospheres, and in millimeters of mercury. (b) Sometimes it is necessary to determine whether an accident victim has suffered a crushed vertebra that is blocking the flow of cerebrospinal fluid in the spinal column. In other cases, a physician may suspect that a tumor or other growth is blocking the spinal column and inhibiting the flow of cerebrospinal fluid. Such conditions ran be investigated by means of the Queckensted test. In this procedure, the veins in the patients neck are compressed lo make the blood pressure rise in the brain. The increase in pressure in the blood vessels is transmitted to the cerebrospinal fluid. What should be the normal effect on the height of the fluid in the spinal tap? (c) Suppose compressing the veins had no effect on the level of the fluid. What might account for this phenomenon?
Find the gauge and absolute pressures in the balloon and peanut jar shown in Figure 11.16, assuming the manometer connected to the balloon uses water whereas the manometer connected to the jar contains mercury. Express in units of centimeters of water for the balloon and millimeters of mercury for the jar, taking h=0.0500 m for each. Figure 11.16 An open-tube manometer has one side open to the atmosphere. (a) Fluid depth must be the same on both sides, or the pressure each side exerts at the bottom will be unequal and there will be flow from the deeper side. (b) A positive gauge pressure Pg=hg transmitted to one side of the manometer can support a column of fluid of height h. (c) Similarly, atmospheric pressure is greater than a negative gauge pressure Pg by an amount hg .The jar's rigidity prevents atmospheric pressure from being transmitted to the peanuts.
A tank with a flat bottom of area A and vertical sides is filled to a depth h with water. The pressure is P0 at the top surface. (a) What is the absolute pressure at the bottom of the tank? (b) Suppose an object of mass M and density less than the density of water is placed into the tank and floats. No water overflows. What is the resulting increase in pressure at the bottom of the tank?
Figure 11.17 shows how a common measurement of arterial pressure is made. Is there any effect on the measured pressure if the manometer is Iowered? What is the effect of raising the arm above the shoulder? What is the effect of placing the cuff on the upper leg with me person standing? Explain your answers In terms of pressure created by the weight of a fluid. Figure 11.17 In routine blood pressure measurements, an inflatable cuff is placed on the upper arm at the same level as the heart. Blood now is detected just below the cuff, and corresponding pressures are transmitted to a mercury-filled manometer. (credit: LJ_S_ Army photo by Spc. Micah E.Clare\4TH BCT)
The human brain and spinal cord are immersed in the cerebrospinal fluid. The fluid is normally continuous between the cranial and spinal cavities and exerts a pressure of 100 to 200 mm of H2O above the prevailing atmospheric pressure. In medical work, pressures are often measured in units of mm of H2O because body fluids, including the cerebrospinal fluid, typically have nearly the same density as water. The pressure of the cerebrospinal fluid can be measured by means of a spinal tap. A hollow tube is inserted into the spinal column, and the height lo which the fluid rises is observed, as shown in Figure P9.83. If the fluid ruses to a height of 160. mm, we write its gauge pressure as 160. mm H2O. (a) Express this pressure in pascals, in atmospheres, and in millimeters of mercury. (b) Sometimes it is necessary to determine whether an accident victim has suffered a crushed vertebra that is blocking the flow of cerebrospinal fluid in the spinal column. In other cases, a physician may suspect that a tumor or other growth is blocking the spinal column and inhibiting the flow of cerebrospinal fluid. Such conditions ran be investigated by means of the Queckensted test. In this procedure, the veins in the patients neck are compressed lo make the blood pressure rise in the brain. The increase in pressure in the blood vessels is transmitted to the cerebrospinal fluid. What should be the normal effect on the height of the fluid in the spinal tap? (c) Suppose compressing the veins had no effect on the level of the fluid. What might account for this phenomenon?
A negative pressure of 25.0 atm can sometimes be achieved with the device in Figure 11.44 before the water separates. (a) To what height could such a negative gauge pressure raise water? (b) How much would a steel wire of the same diameter and length as this capillary stretch if suspended from above? Figure 11.44 (a) When the piston is raised, it stretches the liquid slightly, putting it under tension and creating a negative absolute pressure P=F/A (b) The liquid eventually separates, giving an experimental limit to negative pressure in this liquid.
Review. The tank in Figure P15.13 is filled with water of depth d. At the bottom of one sidewall is a rectangular hatch of height h and width w that is hinged at the top of the hatch. (a) Determine the magnitude of the force the water exerts on the hatch. (b) Find the magnitude of the torque exerted by die water about die hinges.