精选高考物理二轮复习题型专练选择题满分练6新人教版 下载本文

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In its early history, Chicago had floods frequently, especially in the spring, making the streets so muddy that people, horsesto lower the Chicago River or raise the cityAn engineer named Ellis Chesbrough convinced the city that it had no choice but to build the pipes above ground and then cover them with dirt. This raised the level of the city's streets by as much as 12 feet.The next morning at school,Bob’s teacher asks Bob to make sentences with the words “ you,he and I”.Bob 10.stands(stand) up and says,“I am your选择题满分练(六)

14.如图所示是一做匀变速直线运动的质点的位置—时间图象(x-t图象),P(t1,x1)为图象

上一点.PQ为过P点的切线,与x轴交于点Q.则下列说法正确的是( )

x1

A.t1时刻,质点的速率为

t1

x1-x2

B.t1时刻,质点的速率为

t1x1-x2

C.质点的加速度大小为

t21

-t1

D.0~t1时间内,质点的平均速度大小为

x1-x2

B A.x-t图象的斜率表示速度,则t1时刻,质点的速率为,故A错误,B正确;C.

t1 x1-x2

-v0t1v-v0x1-x2

根据图象可知,t=0时刻,初速度不为零,根据a=可知,加速度a=≠,

tt1t21

x1

故C错误;D.0~t1时间内,质点的平均速度大小 v=,故D错误.

t1

15.如图所示,倾角为θ的斜面体c置于水平地面上,小物块b置于斜面上,通过细绳跨过光滑的定滑轮与沙漏a连接,连接b的一段细绳与斜面平行,在a中的沙子缓慢流出的过程中,

a、b、c都处于静止状态,则下列说法不正确的是

( )

A.b对c的摩擦力可能始终增加B.地面对c的支持力始终变大

C.c对地面的摩擦力方向始终向左D.滑轮对绳的作用力方向始终不变

C a中沙子缓慢流出的过程中,a的重力不断减小,与之相连的绳子中的张力也减小,对于

b,它受重力、支持力、拉力和摩擦力而静止,因a、b间质量关系不明确,故b所受的摩擦力可

In its early history, Chicago had floods frequently, especially in the spring, making the streets so muddy that people, horsesto lower the Chicago River or raise the cityAn engineer named Ellis Chesbrough convinced the city that it had no choice but to build the pipes above ground and then cover them with dirt. This raised the level of the city's streets by as much as 12 feet.The next morning at school,Bob’s teacher asks Bob to make sentences with the words “ you,he and I”.Bob 10.stands(stand) up and says,“I am your能始终增加,也可能先向下减少到零后再反向增大,A正确;再以bc为整体,它在一个逐渐减小的拉力作用下静止,因拉力在竖直方向上分量逐渐减小,在水平方向上的分量也逐渐减小,致使地面对c的支持力变大,地面对c的摩擦力方向始终向左,且逐渐减小,故B正确,C错误;绳中的拉力的大小逐渐减小,而绳的一侧平行于斜面,另一侧在竖直方向上,由平行四边形定则知滑

轮对绳的作用力方向始终不变,D正确.

16.通过理想变压器给用电器供电,电路如图甲所示,变压器原线圈匝数n1=1 000匝,副线圈的匝数分别为n2=50匝、n3=100匝.在原线圈ab端接如图乙所示的交变电流,下列说法正确

的是( )

A.交流电的频率为100 Hz

B.U2=50 V,U3=100 V

C.I1∶I2=1∶20

D.闭合开关S,则I1增大

D 交流电的周期为0.02 s,频率为50 HZ,选项A错误;根据变压器的匝数与电压比可知,

U2=

n2U1501 000n3U11001 000

=· V=252 V,U3==× V=502 V,选项B错误;因电n11 000n11 00022

流与匝数之间满足:I1n1=I2n2+I3n3,故选项C错误;闭合开关S,则I3变大,根据I1n1=I2n2+I3n3

可知I1增大,选项D正确,故选D.

17. (2017·福州模拟)在光滑绝缘的水平地面上放置四个相同的可看作质点的金属小球,小球A、B、C位于等边三角形的三个顶点上,小球D位于三角形的中心,如图所示.现让小球A、B、

C都带电荷量为Q的正电荷,让小球D带电荷量为q的负电荷,若四个小球均处于静止状态,则

Q与q的比值为( )

D.3

13

A.B.33

C.3

23

D 设等边三角形的边长为a,由几何知识可知,BD=a·cos 30°·=a,以B为研究对

33

In its early history, Chicago had floods frequently, especially in the spring, making the streets so muddy that people, horsesto lower the Chicago River or raise the cityAn engineer named Ellis Chesbrough convinced the city that it had no choice but to build the pipes above ground and then cover them with dirt. This raised the level of the city's streets by as much as 12 feet.The next morning at school,Bob’s teacher asks Bob to make sentences with the words “ you,he and I”.Bob 10.stands(stand) up and says,“I am your

kQ2kQqQ

象,由平衡条件可知,cos 30°×2=,解得=3,D项正确.

a2BD2q

18.如图所示,一个小球从一定高度h处以水平速度v0=10 m/s抛出,小球恰好垂直撞在倾角θ=45°的斜面的中点P,已知AC=2 m,g=10 m/s,则小球抛出点的高度h及斜面的高度H2

分别为( )

B.10 m、15 mD.15 m、20 m

A.8 m、13 mC.13 m、16 m

v0

C 因小球垂直撞在倾角θ=45°的斜面的中点P,由图知在P点有tan θ=,代入数值得

gt

t=1 s.由平抛规律和几何知识知AC+PCcos θ=v0t,h-PCsin θ=gt2,联立并代入数值得

12

h=13 m,由图知H=2PCsin θ=16 m,C对.

19.(多选)下列说法正确的是( )

A.卢瑟福通过实验发现质子的核反应方程为42He+ 714N→17 8O+1H

B.铀核裂变的核反应方程为235 92U→ 56Ba141+9236Kr+210n

C.设质子、中子、α粒子的质量分别为m1、m2、m3,两个质子和两个中子聚合成一个α粒子,

释放的能量是(m1+m2-m3)c2

D.原子在a、b两个能级的能量分别为Ea、Eb,且Ea>Eb,当原子从a能级跃迁到b能级时,

hc发射光子的波长λ=(其中c为真空中的光速,h为普朗克常量)

Ea-Eb

AD 卢瑟福通过实验发现质子的核反应方程为42He+14 7N→17 8O+1H,选项A正确;铀核裂变的核反应方程为235 92U+10n→141 56Ba+9236Kr+310n,方程式两边的中子不能约去,选项B错误;两个质子和两个中子聚合成一个α粒子,根据爱因斯坦质能方程得ΔE=(2m1+2m2-m3)c,选项C错误;

2

chc

根据Ea-Eb=h,可得辐射的光子的波长为λ=,选项D正确.

λEa-Eb

20.在发射一颗质量为m的地球同步卫星时,先将其发射到贴近地球表面的圆轨道Ⅰ上(离地面高度忽略不计),再通过一椭圆轨道Ⅱ变轨后到达距地面高为h的预定圆轨道Ⅲ上.已知卫星在