皮皮学,免费搜题
登录
搜题
【多选题】
为了增大击球的旋转,应该注意以下几个方面()
A.
减小力臂,使力的作用线远离球心.在打球实际中,就是摩檫球要"薄"一些,向前撞击的力量要小一些
B.
减小击球力量.在力臂固定的情况下,力量越大,力矩也越大.因此,击球力量的大小同乒乓球的旋转也有密切的关系.正如我们在分析击球力量所述,做到这一点的关键是要加快触球瞬间挥拍的速度
C.
增大球拍的粘性.该原理显而易见,因为球拍的粘性越大,摩檫力也越大,所以旋转也越强.正是由于这个原因,使用反胶球拍比使用正胶球拍更容易制造旋转
D.
用球拍的远端触球.用球拍的不同部位触球,对球的旋转也有一定的影响.用靠近球拍远端的一侧触球,由于半径较大,触球点的线速度也较大,因此击球力量越强,产生的旋转也较用靠近拍柄的地方击球要强.所以,打球时应该尽量用靠近球拍拍头的地方触球
拍照语音搜题,微信中搜索"皮皮学"使用
参考答案:
参考解析:
知识点:
.
..
皮皮学刷刷变学霸
举一反三
【单选题】患者,女,56岁。稳定型心绞痛病史,今与邻居争吵时突然发生心前区压榨性疼痛,自行舌下含服硝酸甘油,作用是
A.
增强心肌收缩力
B.
增强心肌做功
C.
增加外周血管阻力
D.
扩张外周血管
E.
扩张静脉系统
【判断题】Read the statement below and decide whether it is true or false.Andrew Keen uses “the law of digital Darwinism” to describe the phenomenon that people who do not scruple to make radical remarks have a...
A.
正确
B.
错误
【单选题】Section B Directions: There are 2 passages in this section. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked A, B, C and D. You shoul...
A.
how long it has been used
B.
what color it is
C.
whether it has been in a collision
D.
whether it leaks oil
【简答题】Task 3 Andrew Pound is an offer to his . Listen to the conversation and decide whether the following statements are true or false. Then write key words to support your answers. 1. The off...
【单选题】患者,女,56岁。稳定型心绞痛病史,今与邻居争吵时突然发生心前区压榨样疼痛,自行舌下含服硝酸甘油作用是
A.
增强心肌收缩力
B.
增加心脏做功
C.
增加外周血管阻力
D.
扩张外周血管
E.
减慢心率
【判断题】收入只包括本企业经济利益的流入,不包括为第三方或客户代收的款项。
A.
正确
B.
错误
【单选题】患者女,56岁,稳定型心绞痛病史,今与其邻居争吵时突发心前区压榨疼痛,自行舌下含服硝酸甘油,作用是
A.
增强心肌收缩力
B.
增强心脏做功
C.
增加外周血管阻力
D.
扩张外周血管
E.
扩张静脉系统
【单选题】Section B Directions: There are 2 passages in this section. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked A, B, C and D. You shoul...
A.
They used to be indifferent and unfriendly to people.
B.
Their staff will explain its strategy impatiently now.
C.
Their attitude worsens because of the terrible situation now.
D.
They never keep people waiting for more than 20 minutes.
【单选题】患者女,56岁。稳定型心绞痛病史,今与邻居争吵时突然发生心前区压榨样疼痛,自行舌下含服硝酸甘油的作用是
A.
增强心肌收缩力
B.
增加心脏做功
C.
增加外周血管阻力
D.
扩张外周血管
E.
扩张静脉系统
【单选题】Section B Directions: There are 2 passages in this section. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked A, B, C and D. You shoul...
A.
by developing a large industrial company
B.
in caring for and improving benefits for the workers and the poor
C.
by furthering Spencer's philosophy
D.
by being a follower of social Darwinism
相关题目: