在做探究“力的合成”的实验时,橡皮筋的一端固定在木板上,用两个弹簧测力计把橡皮筋

题型:不定项选择

问题:

在做探究“力的合成”的实验时,橡皮筋的一端固定在木板上,用两个弹簧测力计把橡皮筋的结点拉到某一确定的点O,以下操作中错误的是 [ ]

A.同一次实验过程中,O点位置允许变动

B.实验中,弹簧测力计必须保持与木板平行,读数时视线要正对弹簧测力计刻度

C.实验中,先将其中一个弹簧测力计沿某一方向拉到最大量程,然后只需调整另一个弹簧测力计拉力的大小和方向,把橡皮筋另一端拉到O点

D.实验中,把橡皮筋的结点拉到O点时,两个弹簧测力计之间夹角必须取90°,以便于算出合力大小

考点:实验:验证力的平行四边形定则
题型:不定项选择

随着网络应用的日益广泛,接入网络和边缘网络的需求也更加复杂多样,企业为了开展电子商务,必须实现与Internet的互联,路由器是实现这一互联网的关键设备,路由器可以位企业提供越来越多的智能化服务,包括安全性、可用性和服务质量(QoS)等。下面是CiscoVLSM子网设计与路由器的路由选择协议(其中路由器的路由选择协议未列出)。
下面以某公司,VLSM(Variable Length Subnet Mask,变长子网掩网)子网的方法。假设该公司被分配了一个C类地址,该公司的网络拓扑结构如图1所示。其中部门A拥有主机数 20、部门B拥有主机数10、部门C拥有主机数20、部门D拥有主机数10,分公司A拥有主机数10、分公司C拥有主机数10。假如分配的网络为192.168.1.0:


1.请为该网络进行子网分割,至少有3个不同变长的子网掩码,请列出你所求的变长子网掩码,并说出理由。

题型:不定项选择

Returning a father's love

He was a single father, raising a 5-year-old boy by himself. He was often worried about his son growing up without a mother to care for him.

One day, he went away on business, leaving the child alone. He worried about the child all the way, not knowing if he had eaten. But his child always told him not to worry. He went home after he finished his work.

When he got home, the child was deep asleep. He was tired out. He was about to sleep when he was surprised to find an overturned(翻倒) bowl of noodles under the quilt, (被子)

He hit his sleeping son angrily ,”Why are you so careless , making the quilt dirty ? Who will wash it ?” It was the first time that he had hit his boy after his wife’s death .

“sorry , but ....” the child explained with tears in his eyes , “This is your supper ,Daddy .” In order to let his father eat dinner the moment he got home , the child prepared two bowls of noddles : one for himself , the other for his father . He was afraid that his father’s noodles would get cold , so he placed them under the quilt .

Hearing this , the father hugged his boy tightly without saying a word .

根据短文内容填空,每空填一词。

小题1:The father often             about his son because the son's mother was_________ .

小题2:The_________ cooked the noodles and put them under the quilt to keep them_________ .

小题3:When the father _________ an overturned bowl of noodles under the quilt , he got __________ .

小题4:After            what his son explained, the father felt__________

小题5:The boy was so            , but he knew how to__________his father's love.

题型:不定项选择

跳台滑雪是勇敢者的运动,它是利用山势特别建造的跳台所进行的。运动员靠着专用滑雪板,不带雪杖在助滑路上获得高速后起跳,在空中飞行一段距离后着陆。这项运动极为壮观。如图所示,设一位运动员由a点沿水平方向跃起,到b点着陆时,测得ab间距离l=40m,山坡倾角θ=30°。试计算运动员起跳的速度和他在空中飞行的时间。(不计空气阻力,g取10m/s2

题型:不定项选择

以下资料中,按等级分组的资料是()

A.治疗效果

B.血型分类

C.某项化验指标的测定结果

D.身高

题型:不定项选择

简述视交叉的解剖关系。

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