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问题 选择题

如图所示是一列向右传播的横波在t=0时刻的波形图，已知此波的波速为2.4m/s，则此波传播的过程中，坐标为（0.9，0）的质点到t=1s时，所通过的路程为（　　）

A．2.56m

B．2.4m

C．0.16m

D．0.02m

答案

由图读出波长为λ=12m，

由波速公式v=

λ
T

得T=

λ
v
=
1.2
2.4
s=0.5s

则t=1s=2T，

简谐运动质点在一个周期内通过的路程为四个振幅，则得质点P在1s内，经过的路程为

S=8A=8×2cm=16cm

故选C

单项选择题

A little boy invited his mother to attend his school’s first teacher-parent meeting. To the little boy’s (1) , she said she would go. This (2) be the first time that his classmates and teacher (3) his mother and he felt (4) of her appearance. Although she was a beautiful woman, there was a severe sear (疤痕) that (5) nearly the entire right side of her face. The boy never wanted to (6) why or how she got the sear.At the meeting, the people were (7) by the kindness and natural beauty of his mother (8) the sear, but the little boy was still embarrassed (尴尬) and (9) himself from everyone. He did, however, get within (10) of a conversation between his mother and his teacher.The teacher asked (11) ," How did you get the scar on your face"The mother replied, " (12) my son was a baby, he was in a room that caught fire. Everyone was (13) afraid to go in because the fire was (14) , so I went in. As I was running toward his bed, I saw a long piece of wood coming down and I placed myself over him trying to protect him. I was knocked (15) but fortunately, a fireman came in and saved both of us. " She (16) the burned side of her face. "This scar will be (17) , but to this day, I have never (18) what I did. "At this moment, the little boy came out running toward his mother with tears in his eyes. He held her in his arms and felt a great (19) of the sacrifice (牺牲) that his mother had made for him. He held her hand (20) for the rest of the day.

第（11）空应选择（）

A．carefully     

B．seriously    

C．nervously    

D．anxiously
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多项选择题

社会角色扮演失常通常包括以下哪几种情况？（）

A.角色不清

B.角色混乱

C.角色冲突

D.角色中断

E.角色越位
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