A composite one-dimensional plane wall is of overall thickness
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- A higher-order differential equation given as y" + p(x)y' g (x)y = O is a homogenous equation, even if p(x) = 0. A higher-order differential equation given as y" + p(x)y' + q(x)y = 0 is also a homogenous equation, even if g(x) = 0. O Only first statement is true. O Only second statement is true. O Both first and second statements are true. O Both first and second statements are false.arrow_forwardQ2. A thermo gate consist of an aluminum plate AB and a magnesium plate CD, each having a width of 15. X mm and fixed supported at their ends as shown in Figure Q2. If the gap between them is 1.5 mm when temperature is T= 25.Y°C, (a) Determine the temperature, T,required to just close the gap. X- The last digit of your matrix number Y- The fifth digit of your matrix number For example, a student with the matrix number CD150150 will have a width of 15.9 mm and T, = 25.7°C (8 marks) (b) Determine the axial force in each plate when the temperature T,becomes 100°C. (7 marks) Assume bending or buckling will not occur. Given E= 68.9 GPa, E, :44.7 GPa, am Oa = 24(10-6)/°C, = 26(10-)/°Carrow_forwardQuestion 1 A copper tube that experience a temperature change is placed between two rigid caps. Four steel bolts are symmetrically arranged parallel to the axis of the tube and are lightly fastened. The copper has a cross-sectional area, length, Young's modulus and coefficient of expansion of 2000 mm², 300 mm, 100 GPa and 16 × 10-6/°C respectively. The steel has a diameter, Young's modulus and coefficient of expansi on of 22 mm, 200 GPa and 12 x 10-6/°C respectively. 1.1 Find the stress in the tube if the temperature of the assembly is raised by 70°Carrow_forward
- Which of the following statements are true? Select one or more: a. Dislocations and defects make thermal transfer easy due to plastic deformation b. Starting at room temperature, the heat conductivity of ceramics goes generally up with increasing temperature c. Starting at room temperature, the heat conductivity of ceramics goes generally down with increasing temperature d. Dislocations and defects make thermal transfer difficult due to phonon scattering e. Heat transfer in solids occurs mainly by waves of atoms vibrating f. Heat transfer in solids occurs mainly by phononsarrow_forwardDetermine the equivalent spring stiffness constant of the following. 235 N/m 155 N/m 350 N/m wwwwwwwwwww 140 N/m 325 N/m ww www 100 N/m www F Answer:arrow_forward2. The coefficient of linear expansion of aluminum is 0.000023/C°. An aluminum rod 5 meters long is heated so that its temperature rises from 25 °C to 50 °C. What is the change in its length? 3. A rectangular block of concrete has a volume of 5 cubic meters and initial temperature of 30°C. By how much will it expand if the temperature rises by 5 C°? The coefficient of thermal expansion of concrete is 10/C". 4. Cylindrical bars of steel and brass with the same diameter and length are joined at one end. The tenperature of the steel bar is 350 K; brass, 500 K. What is the temperature at the junction? The thermal conductivity of steel is 45 W/mol K; brass, 116.arrow_forward
- a. True/False Given 1-D steady-state conduction through a wall with uniform heat generation, the heat transfer (Q. W) is constant throughout the wall. TRUE FALSE b. True/False Consider convection heat transfer acting on an object that is in contact with a fluid at temperature T-. Ifh (the convection coefficient) gets very large. it tends to drive the surface temperature of that object to the fluid temperature T-. TRUE FALSE c. Short answer You need to calculate the temperature at the free end (tip) of a long fin. The boundary condītion you should NOT use is: Circle one! Convective tip Adiabatic tip Infinite finarrow_forward1. Suppose identical solid spheres are distributed through space in such a way that their centers are lie on the points of a lattice, and spheres on neighboring points just touch without overlapping. (Such an arrangement of spheres is called a close-packing arrangement.) Assuming that the spheres have unit density, show that the density of a set of close-packed spheres on each of the four structures (the "packing fraction") is: fcc: bcc: √√2/6=0.74 √√3/8=0.68 SC: π/6=0.52 √√3/16=0.34 diamond:arrow_forwardQuestion 1 A copper tube that experience a temperature change is placed between two rigid caps. Four steel bolts are symmetrically arranged parallel to the axis of the tube and are lightly fastened. The copper has a cross-sectional area, length, Young's modulus and coefficient of expansion of 2000 mm², 300 mm, 100 GPa and 16 x 10-6 /°C respectively. The steel has a diameter, Young's modulus and coefficient of expansi on of 22 mm, 200 GPa and 12 x 10-6/°C respectively. Find the stress in the tube if the temperature of the assembly is raised by 70°C 1.1 1.2 What load will each bolt carry at the raised temperaturearrow_forward
- A one-meter long bar has been heated unevenly, with temperature in °C at a distance z meters from one end at time t given by H(2, t) = 110e 0.06t sin(rz) 0 < <1. (a) On a sheet of paper, sketch a graph of H against z for t = 0 and t = 1. Use this graph to select all correct statements below. A. When t = 0, the rod is the same temperature throughout B. The rod is coldest at the r = 0 end, and warmest at the a = 1 and C. The two ends of the rod remain at 0°C D. The rod is coldest in the middle E. The middle of the rod gets colder over time F. The closer you are to the middle of the rod, the greater the temperature change from t = 0 to t = 1 G. None of the above %3D (b) On a sheet of paper, sketch a graph of H against t for a= 1/8, a= 1/4, and a = 1/2. Use this graph, and your observations from the previous graph, to select all correct statements below. JA. As time goes on, all part of the rod approach the same temperature B. The temperature near the middle of the rod changes most quicky…arrow_forwardPage < 7 Given: An electrical device is insulated on all sides. except for one face. The face is bonded to a 4 mm-thick aluminum plate, which is cooled by air. heat sink → Cross-Sectional area = Im → Electrical device dissipates heat at 104 W/m². → The resistance of the joint between the device and the aluminum plate is 05x10²4 mok/w. → The thermal conductivity of aluminum ts 238 Works. → Too of air 3 278 k and the convective heat transfer coefficient between aluminum and 100 W/m.k. air What is the temperature at the device surface? 0" = 10² W/m²* A=1m² Ts=? Q Search L= 4mm = aoot m k=238 W/mK q=0 Too = 278 k h = 100 W/m² Thermal Contact resistance R = 0.5x10 m² K/W. 99+arrow_forwardQ4. Two are applied to the pipe AB as shown. Knowing that the pipe has inner and outer diameters equal to 35 and 42 mm, respectively. Determine the normal and shear stresses at (a) point a, (b) point b.arrow_forward
- Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning