搜题请搜索小程序“爱下问搜题”
问题 计算题

若我们家里同时使用电饭锅和一盏日光灯，则流经自家电度表的电流有多大？（电饭锅的发热丝电阻约为40Ω，日光灯约1000Ω．）

答案

通过电饭锅的电流为I1===5.5A，

通过日光灯的电流为I2===0.22A，

所以流经自家电度表的电流为I=I1+I2=5.5A+0.22A=5.72A．

单项选择题

Questions from 31 to 35 are based on the following passage: As overseas sales and profits as a percentage of total sales and profits increase, there is likely to be more headquarters’ attention paid to foreign operations. Similarly, there will be pressures to centralize control in order to deal with the growing number of global competitors and the more homogenized(同质的) needs of global consumers. The need for centralization will present more challenges for MNEs in controlling their global operations.One challenge involves management’s position in foreign facilities, where manager may see the erosion of their autonomy over marketing, production, and financial decisions. To keep those managers motivated, the company needs to include more nationalities on boards of directors and use cross-national management teams to develop practices that are globally rather than nationally oriented. But with such cross-national fertilization comes the risk of clashes between cultural traditions.A second challenge for MNEs is a consequence of their size. A number of them already have sales larger than many countries’ GDPs. To manage such organizations may require even greater decentralization and more horizontal communication among subsidiaries in different countries that are mutually dependent on parts, products, and resources. This mutual dependence among subsidiaries may in turn require new hierarchical relationships within the organizational structure.

The better a company’s overseas performance is, the more necessary for the company to（）.

A．centralize its overseas control

B．control its global operations

C．guard against its competitors

D．present more challenges to itself
查看答案
选择题

汽车发动机的额定功率为P1，它在水平路面上行驶时受到的摩擦阻力f大小恒定，汽车在水平路面上由静止开始运动，直到车速达到最大速度Vm。汽车发动机的输出功率随时间变化的图象如图所示。若在0～t1时间内，汽车发动机的牵引力是恒定的，则：（   ）

A．开始汽车做匀加速运动，t1（s）时速度达到v，然后

做匀速运动

B．开始汽车做匀加速运动，t1（s）后做加速度逐渐减小

的加速运动，速度达到Vm后做匀速运动。

C．开始时汽车牵引力恒定，t1（s）后牵引力逐渐减小，

直到与阻力平衡

D．开始时汽车牵引力恒定，t1（s）后牵引力即与阻力平衡
查看答案