(1)磁感应强度的大小;
(2)灯泡正常发光时金属棒的运动速率。
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/3/3c17574d-8b10-443a-ae71-ce6377c12e31.png?resizew=107)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21c280c5f4ae649c3bb1f720633c886c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e6486784415f3537c9a13556c05d893.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/635ccd929471d564cc9d2d96266b34d1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdc1ff55b0d8b8ab417c8da783f2d798.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57052dc43fc8fca68b5943980f6c27a3.png)
A.开始时,活塞下方体积为![]() |
B.温度从![]() ![]() ![]() |
C.温度升至![]() ![]() |
D.温度升至![]() ![]() |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7da1eca235e73bee7ca846e4c3bbdf0b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1fc68374a49a35c9c1d3cc7fca6933d9.png)
A.向上移动,![]() | B.向下移动,![]() |
C.静止不动,增大![]() ![]() | D.向上移动一段距离后,增大![]() ![]() |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d9fd58e71dcae6cafaf9037d20ebd76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6dee8230b383d363fe2056576e25421.png)
A.小球振动的周期为![]() | B.O到P的距离为![]() |
C.小球第3次过P点所需的时间为![]() | D.由S到O的运动过程中小球受力逐渐增大 |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84abbfb85a00f48b5db11eeb76b8d134.png)
A.![]() | B.![]() | C.![]() | D.![]() |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21f3bf70722b22983c120d008d097602.png)
(2)①为了使水能够沿水平方向流出,转动出水管至出水口水平;
②接通电源,待水流稳定后,用米尺测出管口到落点的高度差
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6bdfbeb512754046a3b155a2719e9b0a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1c8d41515532550f96a4a151fda4ac7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e04ab890ece60291e6d6b57e85f8cd56.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc4ef973817d347fc468c0a1f776d798.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22964de2a093c97a8755dbe70487735e.png)
(3)已知出水管管壁的厚度为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c02bc0c74292b1e8f395f90935d3174.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4152bdf9b1b684bcd6b8e6fd5783bc6.png)
(4)抽水时若电机的输出功率恒定,当桶内水面降低时,抽水器的流量
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3606c4a853a6a34cb7f33bea81b15a1f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21c280c5f4ae649c3bb1f720633c886c.png)
(1)正午时大气压仍为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3606c4a853a6a34cb7f33bea81b15a1f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee2196a9fdcef8d0874487c5f85fdb40.png)
(2)若某高处的大气压强为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/903d1257c74820100b1862bf1deecf63.png)
8 . 2023年5月28日,中国商飞交付的全球首架C919,大型客机从上海到北京飞行成功。为研制大型客机,研究人员进行了大量的风洞实验。如图所示,某次实验数据是这样的:在A点以水平速度向左弹出一个质量为
的小球,小球弹出后始终受到水平向右恒定风力的作用。经过一段时间小球将到达B点,B点位于A点正下方
处,重力加速度g取
。下列说法正确的是( )
A.风力大小为![]() |
B.从A到B的运动过程中经过![]() |
C.从A到B的运动过程中小球速度最小值为![]() |
D.小球水平方向的速度为零时,距A点的水平距离![]() |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67ffdfa99f2934dbf4a59167217c7961.png)
(1)小物块第一次到达B点时,重力的功率P;
(2)小物块沿半圆形轨道运动的过程中,摩擦力对小物块做的功W;
(3)B、C两点间的距离s。
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/7/3b5bc77d-a2e5-42b2-aaaf-c9e24daefa52.png?resizew=520)
10 . 如图所示,长方形物块放置在光滑水平地面上,两竖直挡板(侧面光滑)夹在物块的两侧并固定在地面上,现把足够长的轻质硬杆竖直固定在物块上,一根不可伸长的长为L的轻质细线一端固定在杆的上端O点,另一端与质量为m的小球(视为质点)相连,把小球拉到O点等高处,细线刚好拉直,现使小球获得竖直向下的初速度,使小球能在竖直平面内做完整的圆周运动,当小球到达最高点时,物块对地面的压力恰好为0,且此时小球的加速度大小为9g。已知小球在运动的过程中与杆不发生碰撞,重力加速度为g,忽略空气的阻力。
(1)求物块的质量以及小球获得的竖直向下的初速度大小;
(2)若小球运动一周到达O点的等高点时,立即撤掉两侧挡板,物块一直在光滑的水平面上运动,求当小球再次到达最低点时物块的速度大小及细线的拉力大小。