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共查询到19条相似文献，搜索用时 266 毫秒
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0引言本文首先讨论了平面曲线在直线上的投影长函数 ,平面曲线 (图形 )绕一共面直线旋转所得旋转体的体积函数 ,给出了它们的积分表示式 ,进而得出计算旋转体体积的一般积分公式。关于旋转体体积的计算问题 ,一般标准分析教材 [1,2 ] 中只讨论了平面图形绕坐标轴旋转所得旋转体的体积的积分公式 ,为了应用上的便利本文将其推广 ,给出平面图形绕任一共面直线旋转所得旋转体体积计算的一般积分公式。一般认为平面曲线是 (开 )直线段到平面内的一一的 ,双方连续的 ,在上映射的象 .在直线段a≤ t≤ b上引入坐标 t,在平面上引入笛卡尔直角坐标…  相似文献

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《大学数学》2016,(4):112-117

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<正>有关球的组合体问题是高中数学的重要内容之一,也是高考考查的重点.尤其是多面体、旋转体的外接球问题,更是同学们学习的难点.下面通过高考题举例分析这类问题的解答方法,供大家参考.1旋转体的外接球在研究旋转体外接球相关问题时,关键是找到两个旋转体公共旋转轴的轴截面,将立体问题转化成平面问题来解答.  相似文献

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A multisheet plane figure is a projection onto the Euclidean plane of a surface whose every point has a neighborhood biuniquely projectable onto the plane. The notion of a multisheet plane figure is a generalization of the usual notion of a plane figure for the case when the boundary contains self-intersecting curves and pairwise intersecting ones. The medial axis of a usual plane figure is the set of points equidistant from the boundary. In this paper we introduce the notion of the medial axis of a multisheet plane figure and study its properties. Medial axes have numerous applications in engineering and computer science.  相似文献

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<正>You've learned the disk method to use integral finding the volume of solid revolution.You'll learn how to use other method for finding the volume of a special type of solids of revolution.Solids of revolution are used commonly in industry.Sometimes,slicing a solid of revolution results in disks with holes in the middle.It's called washer method.The washer is formed by revolving a rectangle about an axis,as shown in Figure 1&2.  相似文献

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The problem of scattering of a scalar plane wave by a prolatespheroid of revolution is solved for Dirichlet boundary condition,arbitrary major to minor axis ratio, and arbitrary incidentdirection. The solution is obtained by using an iterative methodapplied to solutions of the corresponding potential problemand is expressed as a series of products of Legendre and trigonometricfunctions, and ascending powers of wave number. A recursionrelation for the coefficients in this series is derived.  相似文献

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We have obtained an exact solution of the plane problem for a porous tube rotating around its fixed axis of symmetry. The material of the tube is saturated with an ideal compressible liquid. Within the framework of the Bowen theory, for constructing the initial relations, we take into account the interconnections between stress tensors, strain tensors, relative density of the liquid filler, and varying porosity of the material. We present relations for the radial displacements, components of the stress tensor and densities in the skeleton and liquid filler, and also the porosity and mass concentration of the mixture. We have carried out a numerical analysis of the radial distributions of these characteristics for solid and hollow cylinders made of sandstone and saturated with kerosene. The critical numbers of revolution for tubes of saturated and dry materials have been found.  相似文献

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The problem of the motion of a dynamically symmetric gyrostat without slipping on a fixed horizontal plane is investigated. When the surface of the gyrostat and the distribution of the masses in it satisfy a certain condition, supplementing and developing the results obtained by Mushtari [Mushtari KhM. The rolling of a heavy solid of revolution on a fixed horizontal plane. Mat Sbornik 1932; 39(1, 2):105–26], an explicit form of two first integrals of the equations of motion of the gyrostat, in addition to the energy integral, is presented.  相似文献

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Energy is in general not conserved for mechanical nonholonomic systems with affine constraints. In this article we point out that, nevertheless, in certain cases, there is a modification of the energy that is conserved. Such a function is the pull-back of the energy of the system written in a system of time-dependent coordinates in which the constraint is linear, and for this reason will be called a ‘moving’ energy. After giving sufficient conditions for the existence of a conserved, time-independent moving energy, we point out the role of symmetry in this mechanism. Lastly, we apply these ideas to prove that the motions of a heavy homogeneous solid sphere that rolls inside a convex surface of revolution in uniform rotation about its vertical figure axis, are (at least for certain parameter values and in open regions of the phase space) quasi-periodic on tori of dimension up to three.  相似文献

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We examine curvature properties of twisted surfaces with null rotation axis in Minkowski 3-space. That is, we study surfaces that arise when a planar curve is subject to two synchronized rotations, possibly at different speeds, one in its supporting plane and one of this supporting plane about an axis in the plane. Moreover, at least one of the two rotation axes is a null axis. As is clear from its construction, a twisted surface generalizes the concept of a surface of revolution. We classify flat, constant Gaussian curvature, minimal and constant mean curvature twisted surfaces with a null rotation axis. Aside from pseudospheres, pseudohyperbolic spaces and cones, we encounter B-scrolls in these classifications. The appearance of B-scrolls in these classifications is of course the result of the rotation about a null axis. As for the cones in the classification of flat twisted surfaces, introducing proper coordinates, we prove that they are determined by so-called Clelia curves. With a Clelia curve we mean a curve that has linear dependent spherical coordinates.  相似文献

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The motion of a heavy uniform thin-walled ellipsoid of revolution, completely filled with an ideal incompressible liquid, performing uniform vortex motion is investigated. It is assumed that the ellipsoid is situated on a horizontal plane, from the side of which a normal reaction and a force of viscous sliding friction act on it. The equations of motion of the system, suitable both in the general case and in limiting cases of zero ellipsoid mass or zero liquid mass, are set up. Steady and periodic motions of the ellipsoid with the liquid are obtained. The conditions for uniform rotations of the ellipsoid about a vertically situated axis of symmetry to be stable are obtained.  相似文献

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Equations of a mathematical model for bodies of revolution made of elastic homogeneous and fiber-reinforced materials and subjected to large deformations are presented. The volume content of reinforcing fibers is assumed low, and their interaction through the matrix is neglected. The axial lines of the fibers can lie both on surfaces of revolution whose symmetry axes coincide with the axis of the body of revolution and along trajectories directed outside the surfaces. The equations are obtained for the macroscopically axisymmetric problem statement where the parameters of macroscopic deformation of the body vary in its meridional planes, but are constant in the circumferential directions orthogonal to them. The equations also describe the torsion of bodies of revolution and their deformation behavior under the action of inertia forces in rotation around the symmetry axis. The results of a numerical investigation into the large deformations of toroidal bodies made of elastic homogeneous and unidirectionally reinforced materials under torsion caused by a relative rotation of their butt-end sections around the symmetry axis are presented.  相似文献