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习题练习:Physics Unit12: Sound

 作者: physics 发布日期: 2022-09-26 09:56   总分: 87分  得分: _____________

答题人: 游客未登录  开始时间: 22年08月07日 09:59  切换到: 整卷模式

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1#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Which of the following is a false state haprnu ,q:v,ko18ft- ment?

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2#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  In general, sound is conducted fastest througrk -tu o, 1f)dm05uy zbtjho.2h

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3#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the speed of6tbg *yd 4(dabslo(w) sound in a steel rod?

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4#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  As the temperature of the air increases, what happwkr, ub,g: qd6ens to the velocity of sound? (Assume that alqr:6,,wukg b dl other factors remain constant.)

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5#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Compared to the velocifl u9wl*onh(2uyr +)ity of a 400 Hz sound, the velocity of a 200 Hz sound through airi(u w* 2fnlhruo)l+9y is

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6#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Compared to the wavelength of a 400 Hz sound, the wsb76- l ug6wwaa,*hlvavelength of a 200 Hz sound in aa, 66gwuh wa*llvs7 -bir is

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7#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Sound vibrations with frequencihd7bay* s o/ac3a jiu; 6,bo*mes greater than 20,000 Hz are called

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8#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Sound vibrations with frequency less than 20 f8fve39ppr 0 mdx g6v0Hz are called

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9#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Suppose that a sound source is emitting waves uwal),-:6ug lqb )diacniformly in all directions. If you move to a point twice as far away from the source, the frequency of ,:qdibwua 6-)c)lga lthe sound will be

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10#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  For spherically diverging waves, intensity is proportiona2,(ws*pas gsmzwh(*e; ofo 9dl to

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11#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The intensity of a point source at au5o kc .475x odsqp*rq distance d from the source is I. What is the intensity at a distance 2d from tpcq5osxr q k4 5udo*.7he source?

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12#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  You double your distance from a sound source that is radiayap,8e-qaso k6hj+ ) tting equally in all directions. What happens to the intensity of the sounp s- q6,jot)ahyae 8k+d? It reduces to

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13#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  You double your distance from a sound source that is radiat+7 cg kq for,ob:1ga3ding equally in all directions. What hd3+1cgq rbgo:k7 ofa ,appens to the intensity level of the sound? It drops by

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14#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Which of the following increases as a gvbjl,jg akr6525w/lsound becomes louder?

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15#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  You move slowly toward a spezsl,3 .d(l)b6md1bar b byx,baker emitting a pure tone. What characteristic of the sound i(b.a3 llz ),bmb xd sry,bdb16ncreases?

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16#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What determines "loudness" of aqf w8a7d7or8a musical note?

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17#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What determines the "pitch" ofncy/ 6ux*5 jrr,e ltb9 a musical note?

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18#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  When sound passes from air i6 o(d7vgb an8mnto water

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19#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Pressure and displacemenlte xamzgwq pl 1cw,27a 3196yt waves are

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20#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Consider the standing wave on a guitar ss5f0r -tc1 noo, dmjm5tring and the sound wave generated by the guitar as a result ocod t1-mn,j r05fm5s of this vibration. What do these two waves have in common?

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21#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  In a resonating pipe which is open at both ends, tv65 2c5gmxd2rdfi5t0v) y3 j0kgqm og here

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22#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Consider an open pipe of length L. What are the wavelengths of the/ay 7vh81j;x+bioa joa k o5l7 three lowest tones produced by this piv5/7oihx +7a8bay1ljjok a;o pe?

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23#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The lowest tone to resona*v4w1;lp da- ys*mh;ku3tswdte in an open pipe of length L is 200 Hz. Which one of the following frequencies will not resonate in tupwyt43wdda;* 1 v*s ksm-;hlhe same pipe?

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24#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An open pipe of length L is t ,l r yub 2vwc2i93z-w1t.x ouwy1no (xx-l*mresonating at its fundamental frequency. Which statelxxl cb1-xnuv -wt, roz3 . u9ymtw( i2yw*2o1ment is correct?

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25#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  In a resonating pipe which is open at one endt e,)y h 0k-yhee. no b0o8a8a8ork(zt and closed at the other, there

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26#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Consider a closed pipe of length L. What are the wa l5k4i .ikv:v )vs(fd 3pkgwvl*b3.dbvelengths of the three lowest tones produsb3(.vvifv kkpd w): .b4l *dl3igv5 kced by this pipe?

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27#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The lowest tone to resonate in a closed pis/ 2, skiajlc(pe of length L is 200 Hz. Which of the following frequencies will not resonate in that pslc,j ika2(s/ ipe?

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28#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A pipe of length L closed at one end is resonating at its fundamental fi,km1)mi7 vgvrequency. Which stat17m g v,k)miivement is correct?

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29#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A person stands between two speakers driven by the same source. Each speaker 8lqzd ;p:v vwqy/2 ,ycproduces a tone with a fwd/ ypvz; qcyl8,2v: qrequency of 200 Hz on a day when the speed of sound is 330 m/s. The person is
1.65 m from one speaker and 4.95 m from the other. What type of interference does the person sense?

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30#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  In order to produce beats, the two souj9f ns;tir m14nd waves should have

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31#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Two pure tones are sounded together and a particular beat frequencyq/4i9 cs50,)opin qgkg fmy t9 is heard. Wh4ksg /qt0i gf,on5c ymq p)9i9at happens to the beat frequency if the frequency of one of the tones is increased?

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32#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The Doppler shift ex1yq ++vtx6jy no+ja6r ku5 -laplains

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33#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A sound source approaches a stationary observer. The freqoi f g*yv07n ojmt-igz*a0e/4uency heard by the observvegynj /t40f-i azooi7g *0 m*er is

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34#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A sound source departs from a stationary observer.ghynasw lm n-j,..: y ;lp/9sr The frequency heard by the obssp9n : a yyrw-.;.n/mljslh, gerver is

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35#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  If a jet plane were to double its MACH1.m./d:cc o 5 kzzkvg ,.bxizc-speed, its half-angle will decrease by a factor of . zdk z.o,g/ .c:xcbvkzc5m1i:

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36#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The speed of an ultrasonic sound of frequency 45 kHz in air is 352 z l; +epzh 0q84y.buml+fbf9 lm/s. What is the air 0 b+8+lb ffm;yz.l ep4uqlz9 htemperature?

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37#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the ratio of thqp-fl 0cygha6 )c z16he speed of sound in air at $0 \; ^{\circ}C$ to the speed at $100 \; ^{\circ}C$?

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38#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  On a day when the speed of sound in air is 340 m/s, a bat emits a u,4 c44mjvg6(0r af 0mzutmtdshriek whose echo reaches it 0.0250 s later. How far away was the object that 0fgd ,a juv4m 44m0z (mrutc6treflected back the sound?

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39#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  You shout at a cliff, and hear the echo in 4.00 s. Thebf *c0 h6+ag-/avouir +v)sdo temperature is $0 \; ^{\circ}C$. How far away is the cliff?

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40#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  If you hear thunder 5.0 s after seeing a flash of lig2dscmxn /8y*ayk 1r(x:4 *f lbvza+tvhtning, the distance to the lightning2/+* 1 4 svr(vkcaxbxfd8*y: mnzlty a strike is about

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41#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An echo is heard 2.0 s from a cliff on a day the temperature isbx 0*6anb/ae wvkr 1k ) )/.rftkcx gl0c4gfe9 $15 \; ^{\circ}C$. Approximately how far is the cliff from the observer?

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42#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  On a $30 \; ^{\circ}C$ day, there is an explosion. The sound is heard 3.4 s after seeing the flash. How far away was the explosion?

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43#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  You drop a stone into a deep well and hear the splash 2.5 s later..0nk li3modyc(g*h b -v5fk n/ How deep is the well? (Ignore ahoc* kngi (d0lky nfb.-v/53mir resistance, and assume the velocity of sound is 340 m/s.)

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44#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The wavelength in air of a sound wave of freegtl f qj*gst+y6d-.;6 tx+nuquency 500 Hz is

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45#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Sound traveling in air u3fpr7dzls:, at $23 \; ^{\circ}C$ enters a cold front where the air temperature is $2 \; ^{\circ}C$. If the sound frequency is 1500 Hz, determine the wavelength in the warmer air and in the colder air.

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46#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the intensity level of a sound with intensity */2i zus w-nfen,m9pn$10^{-3} \; W/m^{2}$?

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47#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the intensity of a 7fgg c86ipno4 wby1a c:t7*mn3 0-dB sound?

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48#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the ratio of the intensities of two sounds with intensity levels ofb rk 15e8kp6pr 70 dB and 4bp8rp 1 6erk5k0 dB?

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49#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The intensity level by 15 q f*r1/dug h7)aigb. hengines in a garage is 100 dB. What is the intensity level geng7bgruhf1 h)/.qaid* erated by one engine?

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50#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The intensity at a distance of 6.0 m frombbt2 gxt(ubipi /00zvwl2*sl yr)f/; a source that is radiating equally in all fylix rstg (vp; ti*wblz 02//)2bu0 bdirections is
$6.0 \times 10^{-10} \; W/m^{2}$. What is the power emitted by the source?

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51#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The intensity at a distance of 6.0 m from a source that is radianyak 1ch2pzyb. far(e n0:1) sddbi9)iie3r:ting equally in all directions isne1:k :y pyh(9 fd23iz)e0 ic1b)abradnr. is
$6.0 \times 10^{-10} \; W/m^{2}$. What is the intensity level in dB?

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52#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A barking dog delivers about 1 mgfl,dt qm2+g j(rfzcg9u9gcy)zjg ; :k//- efW of power, which is assumed to be uniformly distributed in all directions. What is the intensity level at azc,jf9/) /ut 2dmrf9jgk(egzf-: gy+q lgc g; distance 5.00 m from the dog?

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53#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The intensity level is 65 dB at a distance 5.00 m from a barking5ccu bce5 r8a. dog. What would be the intensity level if two identical dogs very close to each other a5e5 ub8.ccrc are barking?

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54#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  At a distance of 15 m from a sound source the intensityc-nl cza*7/nq level is 60 dB. What is the intensity level (in a*/7ncl -zncqdB) at a point 2.0 m from the source? Assume that the source radiates equally in all directions.

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55#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The sound intensity level 5.0 m from a ptfpl, dua n8c+-uc:( moint source is 95 dB. At what distance wilu (fpntc+ ca :d-mlu,8l it be 75 dB?

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56#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The third harmonic of a complex fgw hzt1;xb13,rd q.1q h;y f97ij skytone has a frequency of 1200 Hz. What is the frequency of the fourthh1fhi;11,zrjyw;b.tg 9 xk qyds73 qf harmonic?

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57#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The frequency of the third harmonic k cd+7sv13 sato3ti9mh)0tlu -dh5df of an open pipe is 900 Hz. What is the length of the pipe?l 7t)k1cf33t0s uodsvda-m+it 9 d5hh

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58#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The lowest tone to resonate ink9zhc ;t3 0dx )hv,7hij*elmf an open pipe of length L is 400 Hz. What is the frequency of the tj ;kd hl* hz7hvxci,9e 3m0)flowest tone that will resonate in an open pipe of length 2L?

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59#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An organ pipe open at both ends has a length of 0.80 m. If xmg;fl1d 32od the velocity of sound in air is 340 m/s, what o;ddxg31 fm l2is the frequency of the second harmonic?

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60#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 3.00-m long pipe is in a room where .mo+ f ba.rd2x)vykua ;3cs3cthe temperature is $20 \; ^{\circ}C$. What is the fundamental
frequency if the pipe is open at both ends?

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61#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The fundamental frequency in a pipe closed at one end i g)6e8r oobrip-wt:,8xj cs+v6-m mvws 330 Hz. What is the frequency of the thirb8i)6+roe- m wpgvj,tvc6 mr8- o xws:d harmonic?

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62#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the length of the shortest pipe closedgp ov7 fpd3ar.*- wl(;e fioa1 on one end that will have a fundamental fdfl vi ; g7re1pf.a3(owa*op-requency of 60 Hz on a day when the velocity of sound is 340 m/s?

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63#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 3.00-m long pipe is in a room where the tempera trgsn. +rt5xwvpom j69 m:d(1yd+(in ture is $20 \; ^{\circ}C$. What is the fundamental frequency if the pipe is closed at one end?

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64#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 3.00-m long pipe is in a room t f(en9(.sp wiwvy*ao4w)zv9 where the temperature is $20 \; ^{\circ}C$. What is the frequency of the second harmonic if the pipe is closed at one end?

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65#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A closed organ pipe of length 0.75 m is stc79of4 q,moxp f+7j 88glpu5j.g ozplayed when the speed of sound in air is 340 m/s. Wm, 4+p .xjp7tqojf gzsg9lco8f7u 5o8hat is the fundamental frequency?

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66#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Consider two pipes of the same len 6dq)))pcv p rf2 a6cm6ht7jlugth: one is open and the other is closed on one end. If the fundamenl hrpjtm q2v)6 6d)ap7c)ucf6tal frequency of the open pipe is 300 Hz, what is the fundamental frequency of the closed pipe?

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67#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Two adjacent sources each emit a f7 o/9otu,yia ukl o: tz51tbp0requency of 800 Hz in air where the velocity of sound is 340 m/s. How much farther back would sb9 tt/70 z ok1,iyut:ouaolp5 ource 1 have to be moved so an observer in front of the sources would hear no sound?

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68#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Two speakers are placed side by sidev8z bl57wyww6 and driven by the same frequency of 500 Hz. If the distance from a person to one speaker is 5.00 m and the person detects little or no sound, which of the following is a possible the distance from the person to the other speaker? (The sound speed is 7l5wwz68b wyv 340 m/s.)

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69#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Two tunes have frequencies of 440 Hz and/d).9foqu hufdb l;2v 444 Hz. What is the beat frequency?

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70#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A music tuner uses a 550-Hz tuning fork to tune the frequency of a musiz:b:7h afvw(rcal instrument. If the tuner hears a beat frequency of 2 Hz, what is the av :zf(:b hw7rfrequency of the instrument?

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71#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The wavelengths of the sounds produced by two horns are 6 m and 7 m resprh 5:5rol7r;ycfiw3k 7by3ulectively. What beat frequ7wy73 r5loi rkh3 crly5:u;fb ency is heard when the horns are sounded on a day when the velocity of sound is 340 m/s?

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72#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The corresponding violin strings on two violins in an orchestra are f*+,ah)idj3 th 2xfleaound to produce a beat frequency of 2 Hz when a frequency of 660 Hz is played. What percentage change in the tension of one of the strings ji *et3fa, xh+2ad)hlwould bring them to the same frequency?

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73#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An observer approaches a stationary 100m. z;tx(tvynn5kw 0rf .da)8sbn .w/j0-Hz sound source at twice the speed of sound. T ; n0ktv.mnwnt/fw r z.(8.x)5abjdyshe observer hears a frequency of

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74#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A sound source (normal frequency of 1000 Hz) approaches a stationarn7q x2jf 0qufi;ady()y observer at one-half the s7ajq0f xyi f );dn2(qupeed of sound. The observer hears a frequency of

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75#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A sound has a frequency of 1000 H jp, 2* sptxcia2(qup9z. If a listener moves with a speed of 30 m/s away *(ipp2jqc, as9p2xut from the source, what is the frequency heard by the observer? (The sound speed is 340 m/s.)

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76#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A police car has an 800-Hz siren. It is traveling at 35 m/s on a;be 0fegkpy9(;. wotjz e x7 mlf;d(0m day when the speed of sound through air is 340 m/s. The car approaches and passes an observee0 x;w0d l(ff;yoz(gm b;jm97pke.e tr who is standing along the roadside. What change of frequency does the observer hear?

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77#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the frequency heard by a stationary observer when a train approachm1urpc9+on0 pdrd;7; mo74cauf d: upes with a speed of 30 m/s. The frequency of the trainpr74fc;o +0mu m7ncdapou ;p d:dr u19 horn is 600 Hz and the speed of sound is 340 m/s.

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78#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A train is traveling toward you at 120 km/h5op ovy 5aa4a:. The train blows its 400-Hz whistle. Take the speed of sound to be 340 m/s. What freque:5 aa4pa 5vooyncy do you hear?

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79#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  You are moving at 120 km/h toward a stationary train. The train blows its 49q4b1+yyj w inn od0/t00-Hz whistle. Take the speed of sound to be 340 m/s. What b9ot4ynjw /q0nid+1yfrequency do you hear?

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80#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A train is traveling away from you at 120 km/h. Tha;kr;2r)ud4 +o, a 5sjfnfg*jrukxs (e train blows its 400-Hz whistle. Take the speed of sounf5,(gj;;ru*n +r au2 ajos)skrfdk 4xd to be 340 m/s. What frequency do you hear?

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81#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A train is traveling away from you at 120 km/h. It blows its whistle, and)eph 05qw j v:7pcgt.s iu8)aa you hear a tone of 400 Hz. Take the speeigq5)shc:80tu e7va)p .paj wd of sound to be 340 m/s. What is the actual frequency of the whistle?

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82#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The frequency of a train horn is 500 Hz. Assume the sp3r9 )o 6c7yatxs ac4useed of sound in air is 340 m/s. What is the frequency heard by an observer if the observer is moviaa cs6cxu sr3)4t97yong away from the train with a speed of 30.0 m/s?

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83#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The frequency of a train horn is 51uqby 8wb7ftqxns vt: 9-d .)y00 Hz. Assume the speed of sound in air is 340 m/s. What is the frequency heard by an observer if the observer is ap w.ytsd) 9ut7- 8yb1bnqf:x vqproaching the train with a speed of 30.0 m/s?

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84#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Sonar is used to determine the speed o9a2akx hb) fpqt/cgb0q5m ik0k 7s/r 8f an object. A 40-kHz signal is sent out, and a 42-kHz signal is returned. Assume the speed of sound is 345 m/s. How fast is the object moving0 7hk85k q pkfg02/xic)ab m9qbta/rs?

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85#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The half angle of the conical shock ) p5kf ms,x2ez57fzkaqm.uqk+36yt(5vauhm wave produced by a supersonic aircraft is $60^{\circ}$. What is the Mach number of the aircraft?

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86#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A jet flies at a speed of Mach 1.4. What is the half-angle of the conical shob+7it2mek5 drg0 shs *ck wrg0be*sdi7+sth 5m 2k ave formed?

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87#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The Concord airplane flies from the United States toly /v4hj2qieer( n89:l p5 imc Europe with a Mach number of 14qjiiv9 h 5l2y(cer8:m n/ple.05 where the air temperature is $5.0 \; ^{\circ}C$. What is the speed of the plane?

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总分:87分 及格:52.2分 时间:不限时
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