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问题 计算题

在一条长20 cm 的细绳的一端系一个小球，另一端固定在水平桌面上，使小球以5 m/s 的速度在桌面上做匀速圆周运动，求小球运动的向心加速度和转动的角速度．

答案

an=125 m/s2    ω= 25 rad/s

单项选择题

男性，38岁，右侧下颌骨渐进性膨大半年，近来牙齿松动脱落，CT扫描如图所示，请选择最佳答案()

A．动脉瘤样骨囊肿

B．造釉细胞瘤

C．骨软骨瘤

D．牙根囊肿

E．牙龈癌
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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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