Chapter 2: Problem 130
What is the difference between the degree and the order of a derivative?
Chapter 2: Problem 130
What is the difference between the degree and the order of a derivative?
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Get started for freeConsider a homogeneous spherical piece of radioactive material of radius \(r_{o}=0.04 \mathrm{~m}\) that is generating heat at a constant rate of \(\dot{e}_{\mathrm{gen}}=4 \times 10^{7} \mathrm{~W} / \mathrm{m}^{3}\). The heat generated is dissipated to the environment steadily. The outer surface of the sphere is maintained at a uniform temperature of \(80^{\circ} \mathrm{C}\), and the thermal conductivity of the sphere is $k=15 \mathrm{~W} / \mathrm{m} \cdot \mathrm{K}\(. Assuming steady one-dimensional heat transfer, \)(a)$ express the differential equation and the boundary conditions for heat conduction through the sphere, \((b)\) obtain a relation for the variation of temperature in the sphere by solving the differential equation, and \((c)\) determine the temperature at the center of the sphere.
Consider a solid cylindrical rod whose ends are maintained at constant but different temperatures while the side surface is perfectly insulated. There is no heat generation. It is claimed that the temperature along the axis of the rod varies linearly during steady heat conduction. Do you agree with this claim? Why?
Consider a third-order linear and homogeneous differential equation. How many arbitrary constants will its general solution involve?
A spherical container with an inner radius \(r_{1}=1 \mathrm{~m}\) and an outer radius \(r_{2}=1.05 \mathrm{~m}\) has its inner surface subjected to a uniform heat flux of \(\dot{q}_{1}=7 \mathrm{~kW} / \mathrm{m}^{2}\). The outer surface of the container has a temperature \(T_{2}=25^{\circ} \mathrm{C}\), and the container wall thermal conductivity is $k=1.5 \mathrm{~W} / \mathrm{m} \cdot \mathrm{K}$. Show that the variation of temperature in the container wall can be expressed as $T(r)=\left(\dot{q}_{1} r_{1}^{2} / k\right)\left(1 / r-1 / r_{2}\right)+T_{2}$ and determine the temperature of the inner surface of the container at \(r=r_{1}\).
A plane wall of thickness \(L\) is subjected to convection at both surfaces with ambient temperature \(T_{\infty \text { el }}\) and heat transfer coefficient \(h_{1}\) at the inner surface and corresponding \(T_{\infty 2}\) and \(h_{2}\) values at the outer surface. Taking the positive direction of \(x\) to be from the inner surface to the outer surface, the correct expression for the convection boundary condition is (a) \(k \frac{d T(0)}{d x}=h_{1}\left[T(0)-T_{\infty 1}\right]\) (b) $k \frac{d T(L)}{d x}=h_{2}\left[T(L)-T_{\infty 22}\right]$ (c) $-k \frac{d T(0)}{d x}=h_{1}\left(T_{\infty 1}-T_{\infty 22}\right)(d)-k \frac{d T(L)}{d x}=h_{2}\left(T_{\infty \infty 1}-T_{\infty 22}\right)$ (e) None of them
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