您所在的当前位置：高中物理试题 >

向心力与向心加速度

> 如图所示，细杆的一端与一小球相连，可绕过O点的水平轴自由转动现给小球一初速度，使它做圆周运动，图中a、b分别表示小球轨道的最低点和最高点，则杆对球的作用力可能是 [ ] A.a处为拉力，b处为拉力 B.a处为拉力，b处为推力 C.a处为推力，b处为拉力 D.a处为推力，b处为推力

问题：

发布时间：2024-09-10

如图所示，细杆的一端与一小球相连，可绕过O点的水平轴自由转动现给小球一初速度，使它做圆周运动，图中a、b分别表示小球轨道的最低点和最高点，则杆对球的作用力可能是

[ ]
A.a处为拉力，b处为拉力
B.a处为拉力，b处为推力
C.a处为推力，b处为拉力
D.a处为推力，b处为推力

参考答案：

提问用户：6k***tzd

可能感兴趣的题目：

1 下列各项中，属于达·芬奇的代表作的是 ①《蒙娜丽莎》 ②《神曲》 ③《哈姆雷特》 ④《最后的晚餐》 A.①② B.③④ C.②③ D.①④
2 His advertisement income this year is about $36 million, over three times________of last year. A．that B．what C．those D．ones
3 下列实验能达到预期目的是（　　） A．煮沸的1mol•L-1NaOH溶液中滴加FeCl3饱和溶液制备Fe（OH）3胶体 B．用石墨作电极，电解Mg（NO3）2、Cu（NO3）2的混合溶液，确定铜和镁的金属活动性强弱 C．称取19.0g SnCl2，用100mL蒸馏水溶解，配制1.0mol•L-1 SnCl2溶液 D．测定NaCl和NaF溶液的pH，确定F、Cl两元素非金属性的强弱
4 对于一个做匀减速直线运动的物体，在它静止前，下列说法中正确的是（　　） A．速度越来越小 B．速度越来越大 C．加速度越来越小 D．加速度越来越大
5 Considering the boys around Tom a bad influence on him, his parents don’t like him ______ them. A．corresponding with B．fascinating with C．associating with D．conflicting with
6 已知数列满足：是数列的前n项和.数列前n项的积为，且（Ⅰ）求数列，的通项公式；（Ⅱ）是否存在常数a,使得成等差数列？若存在，求出a，若不存在，说明理由；（Ⅲ）是否存在，满足对任意自然数时，恒成立，若存在，求出m的值；若不存在，说明理由.
7 下列化合物中，只有在溶液中才能导电的电解质是（） A．NaCl B．酒精 C．H2SO4 D．KCl
8 There is hardly an environment on earth _____ some species of animals or other have not adapted successfully. A．in which B．on which C．to which D．for which
9 There is a new take on an old tale．It"s the story of the three little pigs and the big bad wolf that blew down a house made of straw and one made of sticks．The only house left standing was the one made of bricks．Now there is new evidence to suggest that houses built with bales（捆）of straw can be very strong． Pete Walker is a professor at the University of Bath in Britain． He and a team of researchers there have built a house made out of straw bale and hemp（大麻） material．During the next twelve months the team will study die effectiveness of these materials in home building．Professor Walker says there are many good reasons for using straw．It"s a relatively inexpensive renewable material that"s quickly and easily available．Straw takes in carbon dioxide as it grows．So it can be seen as having no harmful effects the environment．And the straw bales walls are relatively thick and so all that straw provides very good thermal insulation．So we make buildings that require very little heating in winter or indeed very little cooling in summer．So they require very little additional energy． David Lanfear owns an eco-friendly home building service in the United States called Bale on Bale Construction．He says he laughed when some friends first told him about houses built of straw．But after doing his own research, he learned that building with straw bales makes a lot of sense．He has now helped to build more than ten straw bale houses and says the building material is becoming more widely accepted．To build the houses, he fills a wood frame with tightly packed bales of straw．Next he coats the walls inside and out with layers of clay plaster．He says the common ideas about straw houses continue, including stories about the threat of fire．As a matter of fact, straw bale houses have done well when tested for fire resistance．And his builders use the same building methods as traditional builders to keep out rain．He says we use what we call good shoes and a good hat, and that would be a solid foundation and a really good roof． 68．According to the passage, Pete Walker ____． A．is cooperating with David Lanfear in building houses B．is pretty sure that straw is a good building material C．is studying home building with his team at present D．holds a different view of building materials from David Lanfear 69．If we live in houses built with bales of straw, we ____． A．will be worried about the threat of fire B．need to wear good shoes in severe weather C．can reduce our household expense D．should use a special method to keep out rain 70．In building straw houses, ____． A．a solid foundation and a good roof are necessary B．straw bales have to be tested for fire resistance C．a wood frame of straw should be used as a good roof D．builders should wear good shoes and a good hat 71．Which of the following is the best tide of the passage? A．Houses Made of Straw B．New Meaning Of an Old Tale C．Pete Walker and David Lanfear D．Solid Foundation and Good Roof
10 下列物体质量最接近5×10 8mg的是 A.一头牛 B.一头大象 C.一只苹果 D.一辆自行车