An iron bar 2.0 cm x 3.0 cm x 10.0 cm at a temperature of 95 °C is dropped into a barrel of water at 25 °C. The barrel is large enough so that the water temperature rises negligibly as the bar cools. The rate at which heat is transferred from the bar to the water is given by the expression Q (J/min) = UA (T,- T) where U 0.05 J/(min cm °C)] is a (cm ) is the exposed surface area of the bar, T, and Tw are the surface temperature of the bar and the water temperature, respectively. The heat capacity of the bar is 0.46 J/(g °C). Heat conduction in iron is rapid enough for the temperature T, to be considered uniform throughout the bar. a) Write an energy balance on the bar b) Plot the expected plot of T, versus t and then curve fitting. n')(7.7 g/cm³) = 462 g M = (60 cm)(7.7 g/cm) = 462 g = 0.46 kJ/(kg. C), T = 25°C M 3D160 ст ст C, U = 0.050 J/(min cm2.C) A = 2[(2(3) + (2)(10) + (3)(10)]em² = 112 cm %3D %3D %3! %3D

An iron bar 2.0 cm x 3.0 cm x 10.0 cm at a temperature of 95 °C is dropped into a barrel of water at 25 °C. The barrel is large enough so that the water temperature rises negligibly as the bar cools. The rate at which heat is transferred from the bar to the water is given by the expression Q (J/min) = UA (T,- T) where U 0.05 J/(min cm °C)] is a (cm ) is the exposed surface area of the bar, T, and Tw are the surface temperature of the bar and the water temperature, respectively. The heat capacity of the bar is 0.46 J/(g °C). Heat conduction in iron is rapid enough for the temperature T, to be considered uniform throughout the bar. a) Write an energy balance on the bar b) Plot the expected plot of T, versus t and then curve fitting. n')(7.7 g/cm³) = 462 g M = (60 cm)(7.7 g/cm) = 462 g = 0.46 kJ/(kg. C), T = 25°C M 3D160 ст ст C, U = 0.050 J/(min cm2.C) A = 2[(2(3) + (2)(10) + (3)(10)]em² = 112 cm %3D %3D %3! %3D

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

See similar textbooks

Similar questions

The air velocity in the duct of a heating system is to be measured by a Pitot-static probe inserted into the duct parallel to the flow. If the differential height between the water columns connected to the two outlets of the probe is 3.2 cm, determine (a) the flow velocity and (b) the pressure rise at the tip of the probe. The air temperature and pressure in the duct are 45° C and 98 kPa, respectively
Water (modeled as an incompressible substance) flows steadily through a circular pipe oftotal length ? = 10 m. The mass flow rate through the pipe is ?̇ = 2 kg s⁄ and the watertemperature drops by 25°C as it moves through the pipe. Pressure losses within the pipeare negligible, as are any changes in potential and kinetic energy of the flowing fluid.a) Determine the rate of energy loss from the water as it moves through the pipe. Youmay treat the water as having a constant specific heat (? = 4.18 kJ kg-K⁄ ). Recall thatfor an incompressible substance Δℎ = Δ? + ?Δ?, where Δ? = ∫ ? ?? and ? is thespecific volume of the substance. Your solution should start with an energy balanceon an appropriately defined system/control volume.b) The air surrounding the pipe is at ?∞ = 25°C and the convection coefficient at theouter surface of the pipe is ℎ = 15 W m2-K⁄ . It is also known that the surfaceemissivity of the pipe is ? = 0.3 and the walls of the room where the pipe is locatedare at ?sur =…
Water at 75 degrees Celsius is flowing horizontally at a rate of 1.6 m^3/min in a pipe. It enters a 3-in 45 degree elbow and is diverted upwards into a connecting pipe. The diameter of the outlet is 2in. If the pressure just before the elbow is 78 kPa, determine the magnitude and direction of the force necessary to keep the elbow in place. Assume frictional losses in the elbow are negligible.
The water is supplied at a pressure of 15 N/cm? to an accumulator, having a ram of diameter 2.0 m. If the total lift of the ram is 10 m, determine: (a) the capacity of the accumulator, and (b) total weight placed on the ram (including the weight of the ram). [Ans. (a) 4712.4 kNm, (b) 471240 N]
.........TheGaugePressure 0f the air in an aut0m0bile tire is 25psi, and assuming the ambient atm0sphericPressure is38psi. Express the_abs0lute_pressure_in the tire in bars.
What is the critical value of the pressure coefficient for an airplane flying at 170m/s in air at 2 deg C?
6. Hot water flows through a horizontal steelpipe with diameter (0.25 m) the watervelocity is 5 m/s. The properties of water arep=300 kg/m3 p=3x10-2 kg/m: s. TheReynolds number isO 12000O 12500O 11500O 13500
The ethanol solution is pumped into a vessel 25 m above the reference point through a 25 mm diameter steel pipe at a rate of 10 m3 / hr. The pipe length is 35m and there are 2 elbows. Calculate the power requirements of the pump. The properties of the solution are density 975 kg / m3 and viscosity 4x 10-4 Pa s. a. Reynold number = Answer b. Loss of Energy along the straight pipe = Answer J / kg. c. Losing Energy at curves = Answer J / kg. d. Total energy to overcome friction = Answer J / kg. e. Energy to increase water according to height = Answer J / kg. f. The theoretical energy requirement of the pump ethanol / second = Answer J / kg. g. Actual pump power requirement = Answer watt.
The air velocity in the duct of a heating system is to be measured by a Pitot-static probe inserted into the duct parallel to flow. If the differential height between the water columns connected to the two outlets of the probe is 2.4 cm, determine the flow velocity at the center of the duct in m/s. R of air is 287 J/Kg-K.
A pipe line of length 2000 m is used for power transmission. If 110 kW power is to be transmitted through the pipe in which water having a pressure of 490.5 N/cm2at inlet is flowing. If the pressure drop over the length of pipe is 98.1 N/cm2and ff = 0.0065.Determine:The diameter of the pipe and the volume flow rate; and If a nozzle is introduced at the end of the pipe, what would be its diameter and the power transmitted.
Water is flowing in a 90ο pipe with uniform cross section area of A=0.0083 m2. The velocity along the horizontal direction is v1=6.0 m/s. The pressure at the section 1 is p1=500kPa. Elevation difference and energy losses can be neglected. The density of water is ρ=1000kg/m3. An external force is needed to hold the pipe in equilibrium. (2) Select the correct expression of the external force component in the vertical direction Ry_________ A. B. C. D.
Air flows through a long duct of constant area at 0.15 kg/s. A short section of the duct is cooled by liquid nitrogen that surrounds the duct. The rate of heat loss in this section is 15.0 kJ/s from the air. The absolute pressure, temperature, and velocity entering the cooled section are 188 kPa, 440 K, and 210 m/s, respectively. At the outlet, the absolute pressure and temperature are 213 kPa and 351 K. Compute the duct cross-sectional area and the changes in enthalpy, internal energy, and entropy for this flow. Take C=1 KJ/KgK, C,-0.717 KJ/Kg.K