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问题 多选题

如图所示，一个由绝缘材料制成的轻弹簧水平放置，一端固定于竖直墙上，另一端与一带负电的小球相连，小球置于光滑的绝缘水平面上．当整个装置处于水平向左的匀强电场中时，振子在O点处于平衡状态，在B、C两点间振动．假定在振动过程中小球的电量保持不变，则（　　）

A．小球在由B到O的过程中，弹性势能和电势能减少，动能增加

B．小球在由O到C的过程中，弹性势能增加，电势能和动能减少

C．小球在由B经O到C的过程中，电势能的变化量和弹性势能的变化量大小相等

D．小球在由C到O的过程中，电势能的变化量和弹性势能的变化量大小相等

答案

A、小球做简谐运动，O点是平衡位置，此处弹簧伸长，则知小球所受的电场力方向向右，则小球在由B到O的过程中，电场力做功负功，电势能增加，弹性减小，平衡位置动能最大，则知小球的动能减小．故A错误．

B、小球在由O到C的过程中，弹簧伸长量增大，弹性势能增加，电场力做正功，电势能减小，合力向左，做负功，则动能减小．故B正确．

C、小球在由B经O到C的过程中，动能的变化量为零，根据能量守恒得知，电势能的变化量和弹性势能的变化量大小相等．故C正确．

D、小球在由C到O的过程中，动能减小，弹性势能增加，电势能减小，由能量守恒得知，电势能的变化量大小小于弹性势能的变化量大小．故D错误．

故选BC

单项选择题

下列属于衡量工艺技术方案和工艺流程方案适用性主要内容的有（）。

A．装备水平和自动化程度

B．符合产品方案、产品技术性能、质量标准要求

C．与技术、管理、操作人员团队的素质和能力相适应

D．劳动生产率和成品率
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填空题

Stress is our response to threatening or (1) events. We may experience different levels of stress depending on the (2) , meaning the events or circumstances that cause us to feel stress. Stressors can be classified into (3) main categories: (4) events, personal stressors, and (5) stressors. Cataclysmic events are major events that cause stress (6) , immediately, for a great many people at once. Personal stressors are major life events that create stress, including (7) life events. Background stressors are (8) hassles, or minor irritations, or (9) background stressors. Repeated exposure to stressors has both psychological and (10) consequences. The long- term consequence is that body tissues such as the heart and blood vessels can begin to (11) . The (12) system functions less effectively, and (13) our ability to fight off illnesses.
The General Adaptation (14) explains the sequence of physiological reactions to stress. There are three phases to G. A. S. The first is the " alarm and (15) " phase: we respond with alarm, and take (16) to remove the stressor. The second phase is the (17) stage: we fight against the stressor or try to cope with the stressor. This can lead to the third phase. (18) . The exhaustion phase may be an (19) way of trying to avoid the stressors. The body may be telling us that we need to do whatever is (20) to remove the stressor.

Stress is our response to threatening or (1) events. We may experience different levels of stress depending on the (2) , meaning the events or circumstances that cause us to feel stress. Stressors can be classified into (3) main categories: (4) events, personal stressors, and (5) stressors. Cataclysmic events are major events that cause stress (6) , immediately, for a great many people at once. Personal stressors are major life events that create stress, including (7) life events. Background stressors are (8) hassles, or minor irritations, or (9) background stressors. Repeated exposure to stressors has both psychological and (10) consequences. The long- term consequence is that body tissues such as the heart and blood vessels can begin to (11) . The (12) system functions less effectively, and (13) our ability to fight off illnesses.
The General Adaptation (14) explains the sequence of physiological reactions to stress. There are three phases to G. A. S. The first is the " alarm and (15) " phase: we respond with alarm, and take (16) to remove the stressor. The second phase is the (17) stage: we fight against the stressor or try to cope with the stressor. This can lead to the third phase. (18) . The exhaustion phase may be an (19) way of trying to avoid the stressors. The body may be telling us that we need to do whatever is (20) to remove the stressor.
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