物体运动的速度方向、加速度方向与作用在物体上合力方向的关系是[ ] A.速度方向

题型:不定项选择

问题:

物体运动的速度方向、加速度方向与作用在物体上合力方向的关系是[ ]

A.速度方向、加速度方向、合力方向三者总是相同的

B.速度方向可与加速度方向成任何夹角,但加速度方向总是与合力方向相同

C.速度方向总是和合力方向相同,而加速度方向可能和合力相同,也可能不同

D.速度方向与加速度方向相同,而加速度方向和合力方向可以成任意夹角

考点:牛顿第二定律
题型:不定项选择

当底坑下有能进人的空间时,底坑地板的强度应能承受不小于()的负荷.

A.3000

B.500

C.5000

D.6000

题型:不定项选择

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

All over the world people enjoy sports. Sports help to keep people healthy, happy and help them to live longer.

__小题1:__   They buy tickets or turn on their TVs to watch the games. Often they get very excited when “their” player or team wins.   __小题2:__   Football, for example, has spread around the world. Swimming is popular in all countries near the sea or in those with many rivers. What fun it is to jump into a pool or lake, whether in China, Egypt or Italy!   __小题3:__   Think how many people love to skate or ski in Japan, Norway or Canada.

Some sports or games go back to thousands of years, like running or jumping. Chinese boxing, for example, has a very long history. But basketball and volleyball are rather new. Neither one is a hundred years old yet.   __小题4:__   Water­skiing is one of the newest in the family of sports.

People from different countries may not be able to understand each other, but after a game they often become good friends.   __小题5:__   One learns to fight hard but fight fair, to win without pride and to lose with grace.

A.And think of people in cold countries.

B.Sports help to train a person's character.

C.Not a few people like sports in the world.

D.Many people like to watch others play games.E. People aren't inventing new sports or games.

F. Some sports are so interesting that people everywhere go in for them.

G. People are inventing new sports or games all the time.

题型:不定项选择

对于牵引重载列车的机车要求有足够大的功率和足够大的()。

题型:不定项选择

70°探头探测60Kg/m轨,声程为250mm时,螺孔反射波应在荧光屏刻度()左右显示。

A、6

B、7

C、8

D、9

题型:不定项选择

保险公估报告的生效需要( )。

A.由委托人签名表示同意
B.由保险人签名表示同意
C.由保险合同的各方当事人共同签名
D.由参与公估过程的保险公估人员和保险公估机构的负责人签名

更多题库