各线性电阻的电压、电流如题1-3图所示。试求图中的未知量。

A . 图1 B . 图2 C . 图3 D . 图4

<img src='https://img2.soutiyun.com/ask/2020-09-23/969705165087342.png' /> (1)A、B点的相对压强(用kN/m²表示). (2)A、B点的绝对压强(用米水柱高度表示). (3)容器底面上的总压力(相对压力).

在题2．27图所示电路中，对称负载连成三角形，已知电源电压UL=220 V，各电流表读数均为38 A。试求(1)当B线断开时，图中各电流表的读数；(2)当AC相负载断开时，图中各电流表的读数。 <img src='https://img2.soutiyun.com/ask/uploadfile/10374001-10377000/b1d6841abcf8b603feda441232220fc4.jpg' />

如题[84]图所示为水电站压力输水管,其直径d=1m,静水头h=100m,试求:(1)当钢管的允许拉应力[σ]=1.37×10⁵kN/m³时,管壁的厚度δ.(2)当管壁的厚度δ=5mm时,管壁的环向与轴向拉应力. <img src='https://img2.soutiyun.com/ask/2020-09-23/96971114423233.jpg' />

在题5-7-5图所示的电阻电感串联电路中,若电流i(t)=0.8Ssin314t A,试求电压u_R(t)、u_L(t)和u(t),并绘出波形图和相量图. <img src='https://img2.soutiyun.com/ask/2020-10-10/971171923335419.png' />

<img src='https://img2.soutiyun.com/shangxueba/ask/50805001-50808000/50806402/967198328638004.png' />

由下式给出：<img src='https://img2.soutiyun.com/ask/2020-07-14/963589443855635.png' />。 分析:应用安培环路定理求解。注意环路中电流的计算，应该是先求出载流导体内电流密度，再求出穿过环路的电流。 <img src='https://img2.soutiyun.com/ask/2020-07-14/963589465464871.png' />

<img src='https://img2.soutiyun.com/ask/uploadfile/5364001-5367000/2968ad2b913847aaeafa85b7fd6637c5.jpg' />

<img src='https://img2.soutiyun.com/ask/uploadfile/9063001-9066000/3434604626ce5b1833fabc88528eca52.jpg' />

<img src='https://img2.soutiyun.com/ask/2020-10-06/97086491567492.png' />

<img src='https://img2.soutiyun.com/ask/2020-08-25/967204245200412.png' />

电路如题1-11图所示，试求(1)图(a)中电流i₁和电压u_ab;(2)图(b)中电压u_cb。 <img src='https://img2.soutiyun.com/ask/2020-08-20/966768174350855.png' /><img src='https://img2.soutiyun.com/ask/2020-08-20/966768181740278.png' />

电路如题6-4图所示，已知电感电流iL(0_)=0，t=0时闭合开关，求t≥0的电感电流和电感电压。 <img src='https://img2.soutiyun.com/ask/2020-08-20/966784685280226.png' />

若题2-1-2图所示电路中电沉源的电流减小一半(即为2A),试根据线性电路的齐次性和可加性求电压U. <img src='https://img2.soutiyun.com/ask/2020-10-09/971097219114177.jpg' />

<img src='https://img2.soutiyun.com/ask/2020-10-09/971114311942831.jpg' />

圆弧门如题[69]图所示,门宽b=2m,圆弧半径R=2m,圆心角α=90°,上游水深H=5m,试求:(1)作用在闸门上的水平总压力及作用线位置. (2)作用在闸门上的铅直总压力及作用线位置. (3)忽略门的重量,求开门所需的力F. (4)求作用于铰链o的力矩. <img src='https://img2.soutiyun.com/ask/2020-09-23/969710039766158.png' />

<img src='https://img2.soutiyun.com/ask/2020-07-14/963588454692058.png' /> 分析:微分半圆柱形金属薄片，对微分电流dI应用无限长载流直导线产生的磁场公式求解 。 并将场强矢量<img src='https://img2.soutiyun.com/ask/2020-07-14/963588473652142.jpg' />分解后再积分求解总的磁感应强度。注意利用场的对称性。

<img src='https://img2.soutiyun.com/ask/2020-10-09/971091491072552.png' />

A．0.375A B．0.25A C．0.125A D．0.1875A

题7-2图所示各电路中开关S在t=0时动作，试求各电路在t=0，时刻的电压电流。已知题7-2图(d)中的<img src='https://img2.soutiyun.com/ask/2020-08-24/96707702037258.png' />。 <img src='https://img2.soutiyun.com/ask/2020-08-24/96707704860863.png' />

<img src='https://img2.soutiyun.com/ask/2020-08-24/967136592941634.png' /><img src='https://img2.soutiyun.com/ask/2020-08-24/967136602053155.png' /><img src='https://img2.soutiyun.com/ask/2020-08-24/967136609348572.png' /><img src='https://img2.soutiyun.com/ask/2020-08-24/967136618306084.png' /> <img src='https://img2.soutiyun.com/ask/2020-08-24/967136626942578.png' />

电路如题6-6图所示，其中R=2，L=1 H，C=0.01 F，uc(0)=0若电路的输人电流为 <img src='https://img2.soutiyun.com/ask/2020-08-23/967074442967253.png' /> <img src='https://img2.soutiyun.com/ask/2020-08-23/967074454682874.png' /> 试求两种情况下，当1＞0时的u_R、u_L和u_C值。 <img src='https://img2.soutiyun.com/ask/2020-08-23/967074466148894.png' />