Physics Unit12: Sound - 51fly国际课程 (51fly.win)

标记此题

1#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Which of the following is a false statemenaj83i k,0 dfjlt?

A. Sound waves are longitudinal pressure waves.

B. Sound can travel through a vacuum.

C. Light travels very much faster than sound.

D. The transverse waves on a vibrating string are different from sound waves.

E. "Pitch" (in music) and frequency have approximately the same meaning.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

2#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

In general, sound is conductgd,lg0ho7 1.biz uc7yed fastest through

A. gases.

B. liquids.

C. solids.

D. a vacuum.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

3#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

What is the speed of sound in a stq g)nv-5vpo+a eel rod?

A. 1500 m/s

B. 3000 m/s

C. 5000 m/s

D. 8000 m/s

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

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 happens to the velocity of sxq vx0zpv7b 1b66/ zgjound? (Assume that all other factor6 vvzpz7b6g /b10xqxj s remain constant.)

A. It increases.

B. It decreases.

C. It does not change.

D. It increases when atmospheric pressure is high and decreases when the pressure is low.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

5#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Compared to the velocity of a 400 Hz sound, tnb 8 +oot0oj4zhe velocity of a 200 Hz sound through n o +8zoj4t0boair is

A. twice as great.

B. the same.

C. one-half as great.

D. none of the above

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

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 wavelenxh 6 /w7*qqf c25wm+qxraxog)gth of a 200 Hz sound in fm*xxhx6aw25o qr)c+ w7/q gqair is

A. twice as long.

B. the same.

C. one-half as long.

D. none of the above

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

7#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Sound vibrations with freqr:c fj-y tc*r(uencies greater than 20,000 Hz are called

A. infrasonics.

B. ultrasonics.

C. supersonics.

D. none of the above

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

8#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Sound vibrations with frequency less than 20 Heaf o5 i,w5rych1 6,h2w9 w 6kzwhofh,z are called

A. infrasonics.

B. ultrasonics.

C. supersonics.

D. none of the above

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

9#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Suppose that a sound sou-pwme js98.ek rce is emitting waves uniformly in all directions. If you move to a point twice as far away from the sjpw -e.kems98ource, the frequency of the sound will be

A. unchanged.

B. half as great.

C. one-fourth as great.

D. twice as great.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

10#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

For spherically diverginvr1xgccgu2i ,6vx4*u k aw6h3 g waves, intensity is proportional to

A. $R^2$

B. $R$

C. $1/R$

D. $1/R^2$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

11#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The intensity of a point source at a distance d from the sourc7x2b3hvdnat*3z7s,f q kk)z 4qrw)dx e is I. What is the intensit,4th7 32*d n3vq 7x)) qaw szdzbfkxkry at a distance 2d from the source?

A. $4 \; I$

B. $2 \; I$

C. $I/2$

D. $I/4$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 radiating equ9grrp t8jw. -wef i/z;u wuv31ally in all directions. What happens to the intensity of the sound? Ipu t wguwrf8/v-.ze w;i1j39rt reduces to

A. one-half its original value.

B. one-fourth its original value.

C. one-sixteenth its original value.

D. none of the above

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

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 tha8e50 aiog hdxij49ds6 t is radiating equally in all directihj ie0g94id68 oxsad5ons. What happens to the intensity level of the sound? It drops by

A. 2 dB

B. 3 dB

C. 6 dB

D. 8 dB

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

14#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Which of the following increases4gwkw k6 ga kd/(yi/xrx7*c4f as a sound becomes louder?

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

15#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

You move slowly toward a speaker emitting a pure tone. What chare vd)v4 b6c9 s*/hyzikacteristic of the sound in6i/ 9ysch*ke)dvv 4bz creases?

A. frequency

B. amplitude

C. wavelength

D. period

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

16#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

What determines "loudness" 1cz c 4za*7b/ 6ayubcmof a musical note?

A. frequency

B. velocity

C. phase

D. amplitude

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

17#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

What determines the "pitch" of a musical not(j: 0bq3p)sw w 1vew dpus58zne?

A. amplitude

B. wavelength

C. frequency

D. phase

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

18#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

When sound passes frombexh/:eu*,l/rfu5b7 pk( hdj air into water

A. its wavelength does not change.

B. its frequency does not change.

C. its velocity does not change.

D. all of the above

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

19#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Pressure and displacement waves ar7p gj n.gb1.ohe

A. in phase.

B. $45^{\circ}$ out of phase.

C. $90^{\circ}$ out of phase.

D. $180^{\circ}$ out of phase.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

20#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Consider the standing wavjig2 ij:k fo);aa-3 e-fd7zzie on a guitar string and the sound wave generated by the guitar as a result of idag;3ek-a- zjz7f j:) if 2iothis vibration. What do these two waves have in common?

A. They have the same wavelength.

B. They have the same velocity.

C. They have the same frequency.

D. More than one of the above is true.

E. None of the above is true.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

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 endshnj( 39-wl)bjyi 7fa q2zi6 qa, there

A. are displacement nodes at each end.

B. are displacement antinodes at each end.

C. is a displacement node at one end and a displacement antinode at the other end.

D. none of the above

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 thre.;nmjiotny8 ax *x, 0ae lowest tonay 8ni0 a nmjt;,xxo*.es produced by this pipe?

A. 4L, 2L, L

B. 2L, L, L/2

C. 2L, L, 2L/3

D. 4L, 4L/3, 4L/5

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

23#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The lowest tone to resonate in an open pipe of length L is 200 bu / xh8sgnk75g0p gvd3zmj5.Hz. Which one of the following frequencies will not resonate in xp5u gng/5bhdk. g8j3m7vsz0the same pipe?

A. $400 \; Hz$

B. $600 \; Hz$

C. $800 \; Hz$

D. $900 \; Hz$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

24#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An open pipe of length L is resonating at itz4 d s0)1cn ig6/ua.0.cvslsu3exc ap s fundamental frequency. Which statemenlcd0)0pv.aa.xse/3 4uni g c1z uscs 6t is correct?

A. The wavelength is 2L and there is a displacement node at the pipe's midpoint.

B. The wavelength is 2L and there is a displacement antinode at the pipe's midpoint.

C. The wavelength is L and there is a displacement node at the pipe's midpoint.

D. The wavelength is L and there is a displacement antinode at the pipe's midpoint.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 enul 3n )crw0nz8d and closed at the other, there

A. are displacement nodes at each end.

B. are displacement antinodes at each end.

C. is a displacement node at the open end and a displacement antinode at the closed end.

D. is a displacement node at the closed end and a displacement antinode at the open end.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 wavelengtnt.v-+ xd pr0ths of the three lowest tones x-p+d .tr0tnv produced by this pipe?

A. 4L, 2L, L

B. 2L, L, L/2

C. 2L, L, 2L/3

D. 4L, 4L/3, 4L/5

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

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 pipe of length L*a c6l1sl,+ m rbepy5l is 200 Hz. Which of thel5m a ls,6ecrb ylp+1* following frequencies will not resonate in that pipe?

A. $400 \; Hz$

B. $600 \; Hz$

C. $1000 \; Hz$

D. $1400 \; Hz$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

28#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A pipe of length L closed hw8tdrqyf-1*:6dfi*(c fa 3mrv1gmu nxq7k+ at one end is resonating at its fundamental frequency. Which statement is cymgi(-n8tdw7kv * faf fm61xuc +1*h rqqr3: dorrect?

A. The wavelength is 4L and there is a displacement node at the pipe's open end.

B. The wavelength is 4L and there is a displacement antinode at the pipe's open end.

C. The wavelength is L and there is a displacement node at the pipe's open end.

D. The wavelength is L and there is a displacement antinode at the pipe's open end.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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. gq( 3g74bzt l nwo,ibp8:d7bcEach speaker produces a tone with a frequency of 200 Hz on a day when the speed of sound is 330 m/s. w (z3cngbp ib8 7o7tq:4lbgd, The person is
1.65 m from one speaker and 4.95 m from the other. What type of interference does the person sense?

A. constructive

B. destructive

C. both constructive and destructive

D. neither constructive nor destructive

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

30#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

In order to produce beats, the two so2kkj4-c6se qw( u, gtt(xdcv9und waves should have

A. the same amplitude.

B. slightly different amplitudes.

C. the same frequency.

D. slightly different frequencies.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 fra+;a x70 myaes5 gxk-vequency is heard. What happens to the beat frequency if thesae+m x0v-gk;aa7yx5 frequency of one of the tones is increased?

A. It increases.

B. It decreases.

C. It does not change.

D. It could either increase or decrease.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

32#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The Doppler shift expleay1u(9sjf yli z 5w07ains

A. why the siren on a police car changes its pitch as it races past us.

B. why a sound grows quieter as we move away from the source.

C. how sonar works.

D. the phenomenon of beats.

E. why it is that our hearing is best near 3000 Hz.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 frequew8 hgk( aw)+-zthi2z4so/2bi tmafh .ncy heard by the observsoh i22 4w)i f+b(atm8 .h-ktwghz /zaer is

A. higher than the source.

B. lower than the source.

C. the same as that of the source.

D. equal to zero.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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. The frequency hexazpxq 1w,m 7):bgw(4cdo r3zard by the observer 34 mprd ()zc7qb1 ,o:xgwzwax is

A. higher than the source.

B. lower than the source.

C. the same as that of the source.

D. equal to zero.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

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 MACH-sn*2)rlhto z+gp2bt 0hpeed, its half-angle will decrease by a h2 )onbgt+t2l0*h r pzfactor of:

A. 1/2

B. 2

C. $\sin^{-1} (1/2)$

D. none of the above

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

36#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The speed of an ultrasonic sound of frequenc 35 m,2vwrlzeoy 45 kHz in air is 352 m/s. What is the air temperaowv53 lz2,rm eture?

A. $33 \; ^{\circ}C$

B. $34 \; ^{\circ}C$

C. $35 \; ^{\circ}C$

D. $36 \; ^{\circ}C$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

37#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

What is the ratio of the speed of sound in ahv- (adc8 ,tauir at $0 \; ^{\circ}C$ to the speed at $100 \; ^{\circ}C$?

A. 0.75

B. 0.85

C. 0.95

D. 1.1

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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/,) vzvgqb7sp1c ulqzz:+g-n58qqap7 s, a bat emits a shriek whose echo reaches it 0.0250 s later. How far away was the object thp 17u+zqncvlp s - 7za,8v:qqbggq)5 zat reflected back the sound?

A. $4.25 \; m$

B. $8.50 \; m$

C. $0.425 \; m$

D. $0.850 \; m$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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. The temperature is-vwk c/jr50 th $0 \; ^{\circ}C$. How far away is the cliff?

A. $662 \; m$

B. $680 \; m$

C. $1320 \; m$

D. $1760 \; m$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

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 flav5a . rdot2*id(+;(ez nlcayksh of lightning, the distance to the lightning strike dkn (iaotled+*y5; 2(zrva. cis about

A. 600 m

B. 1200 m

C. 1700 m

D. 2200 m

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 o3:ysssy/ e a(on a day the temperature is $15 \; ^{\circ}C$. Approximately how far is the cliff from the observer?

A. $85 \; m$

B. $170 \; m$

C. $340 \; m$

D. $680 \; m$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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?

A. $0.10 \; km$

B. $0.75 \; km$

C. $1.2 \; km$

D. $1.5 \; km$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 hnw;zhwrzz.( bf1t6 2oear the splash 2.5 s later. How deep is wo. (f;zw62h btnr1 zzthe well? (Ignore air resistance, and assume the velocity of sound is 340 m/s.)

A. $25 \; m$

B. $27 \; m$

C. $29 \; m$

D. $31 \; m$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

44#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The wavelength in ai hm (ccha20 gn:2po5m bcm;jp0r of a sound wave of frequency 500 Hz is

A. 0.69 m

B. 0.75 m

C. 1.5 m

D. 1.8 m

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

45#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Sound traveling in air a8 c,dww)m jz7ot $23 \; ^{\circ}C$ 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.

A. 0.230 m, 0.221 m

B. 0.221 m, 0.230 m

C. 0.321 m, 0.254 m

D. 0.254 m, 0.321 m

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

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 w 56gbs-pjbe;cith intensity $10^{-3} \; W/m^{2}$?

A. $30 \; dB$

B. $60 \; dB$

C. $90 \; dB$

D. $96 \; dB$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

47#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

What is the intensity of a 70-d/l g5)k sbuh1bB sound?

A. $10^{-4} \; W/m^{2}$

B. $10^{-5} \; W/m^{2}$

C. $10^{-6} \; W/m^{2}$

D. $10^{-7} \; W/m^{2}$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

48#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

What is the ratio of the intensi m, r f0:ituaupxqa/);ties of two sounds with intensity levels of 70 dB an:,u i)p ;/q ufxta0amrd 40 dB?

A. 10:1

B. 100:1

C. 1000:1

D. 10,000:1

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

49#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The intensity level by 15 en fe.d(7mf*lfu gines in a garage is 100 dB. What is the intensity level generated by one engfe*(f ud f7m.line?

A. $67 \; dB$

B. $13 \; dB$

C. $44 \; dB$

D. $88 \; dB$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 from a source that is radiating equally 6cn 8av/u ipp*mpy9u/ in all directions pmu/p 8ian 6yu/c*v9pis
$6.0 \times 10^{-10} \; W/m^{2}$. What is the power emitted by the source?

A. $2.1 \times 10^{-8} \; W$

B. $2.7 \times 10^{-7} \; W$

C. $2.1 \times 10^{-6} \; W$

D. $2.7 \times 10^{-5} \; W$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

51#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The intensity at a d4y z ef,zbg+ 2ni uk7s+ry*of5istance of 6.0 m from a source that is radiating equally in 7b2y,zgei ko*+4su ff 5nz+ryall directions is
$6.0 \times 10^{-10} \; W/m^{2}$. What is the intensity level in dB?

A. $18 \; dB$

B. $23 \; dB$

C. $28 \; dB$

D. $32 \; dB$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

52#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A barking dog delivers about 1 mW of power, t.2gt+v hzop:8 u*k g7kk p-dawhich is assumed to be uniformly distributed in all directions. What is the intensity level atut-vk pta dkh+8:z7*kp.go g2 a distance 5.00 m from the dog?

A. $61 \; dB$

B. $63 \; dB$

C. $65 \; dB$

D. $68 \; dB$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 barking dog. Whatsk/wd, +1aogjs89usg w/k8h(qhq n n 1 would be the intensity level if two identdq8as u nognw,( k1wh9+shjs/1/ k8qg ical dogs very close to each other are barking?

A. $65 \; dB$

B. $68 \; dB$

C. $130 \; dB$

D. $136 \; dB$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 intensity ldfe *kid );2jwevel is 60 dB. What is the intensity lev*e;w2j) dfkidel (in dB) at a point 2.0 m from the source? Assume that the source radiates equally in all directions.

A. $55.7 \; dB$

B. $57.5 \; dB$

C. $75.5 \; dB$

D. $77.5 \; dB$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 poinaz- x0wvbp 5hgy6j/8 dt source is 95 dB. At what distance will it be 75y zhj8d pw6/bgx5 va-0 dB?

A. $25 \; m$

B. $50 \; m$

C. $75 \; m$

D. $225 \; m$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

56#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The third harmonic of a complf6;dpy x 4hmjs *1dgv r+ly0x*ex tone has a frequency of 1200 Hz. What is the frequency of the fourth 4m h*ld*1; vpx sy0+xrd 6fgjyharmonic?

A. $400 \; Hz$

B. $900 \; Hz$

C. $1600 \; Hz$

D. $4800 \; Hz$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

57#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The frequency of the third harmonic ok-womp1eafi3w.rgpt v9(3v 4o3k 5 zif an open pipe is 900 Hz. What is the length of p 3iw -imep.4o3 (wktroav9135f zg kvthe pipe?

A. $0.189 \; m$

B. $0.283 \; m$

C. $0.567 \; m$

D. $1.13 \; m$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

58#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The lowest tone to resonate in an open pipe of length L is 400 Hz. What is th 296rdma f1q0gj2gegme frequency of the lowest tone that will resonate in an open prqm0gm9g6a 22j dgf1eipe of length 2L?

A. $800 \; Hz$

B. $200 \; Hz$

C. $1600 \; Hz$

D. $100 \; Hz$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 the velocity of soun48/dx mq4 osajd in a4a/mo sq 48xjdir is 340 m/s, what is the frequency of the second harmonic?

A. $213 \; Hz$

B. $425 \; Hz$

C. $638 \; Hz$

D. $850 \; Hz$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

60#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A 3.00-m long pipe is iz4ckb+g 1uf *on a room where the temperature is $20 \; ^{\circ}C$. What is the fundamental
frequency if the pipe is open at both ends?

A. $57 \; Hz$

B. $114 \; Hz$

C. $29 \; Hz$

D. none of the above

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 is 330 Hz. What i7(yxag ,i3mgts the friatyx3, 7(gm gequency of the third harmonic?

A. $110 \; Hz$

B. $220 \; Hz$

C. $660 \; Hz$

D. $990 \; Hz$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

62#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

What is the length ofv.4f06z -zkp sq/sfw s the shortest pipe closed on one end that will have a fundamental frequency of 60 Hz on a day when the velocity ofs fsvwpz.-kf0z 46q/ s sound is 340 m/s?

A. $1.24 \; m$

B. $1.42 \; m$

C. $2.14 \; m$

D. $4.12 \; m$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 temperatunq5keg/f 9/fhre is $20 \; ^{\circ}C$. What is the fundamental frequency if the pipe is closed at one end?

A. $57 \; Hz$

B. $114 \; Hz$

C. $29 \; Hz$

D. none of the above

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 where the tempera-ewp2gyv4 6oj41 oqh+lex m.-zb+jg sture is $20 \; ^{\circ}C$. What is the frequency of the second harmonic if the pipe is closed at one end?

A. $57 \; Hz$

B. $114 \; Hz$

C. $29 \; Hz$

D. none of the above

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 6vxhz5 +2kt* (firzeo m is played when the speed of sound in air is 340 m/s. What is the fundamental frequenc2 r vizt+h oe6f(k*5zxy?

A. $57 \; Hz$

B. $113 \; Hz$

C. $170 \; Hz$

D. $227 \; Hz$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

66#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Consider two pipes of the same length: onej v wm7cx 3m)oh()41+nqjlko e is open and the other is closed on one end. If the fundamental frequency of the open pipjmj(eo 73loxkn)q 1w mh) 4c+ve is 300 Hz, what is the fundamental frequency of the closed pipe?

A. $150 \; Hz$

B. $300 \; Hz$

C. $450 \; Hz$

D. $600 \; Hz$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

67#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Two adjacent sources each emit a frequency of 800 Hz ehgziow z2d 9,2+/x jfin air where the velocity of sound is 340 m/s. How much farther back would source 1 have to be moved so an observer inz2+ d wgo xfjz2/e9i,h front of the sources would hear no sound?

A. $0.123 \; m$

B. $0.321 \; m$

C. $0.213 \; m$

D. $0.312 \; m$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

68#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Two speakers are placed side pk5pexp t3oe.)60gua by side 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 k ug6o)p.t0e 3ppa5 exof the following is a possible the distance from the person to the other speaker? (The sound speed is 340 m/s.)

A. $7.7 \; m$

B. $8.1 \; m$

C. $8.4 \; m$

D. $9.1 \; m$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

69#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Two tunes have frequencies o j 4;p3os,7c*sjhdv:gfal m0u p 5+/xsqzhp b,f 440 Hz and 444 Hz. What is the beat frequency?

A. $4 \; Hz$

B. $442 \; Hz$

C. $884 \; Hz$

D. none of the above

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 a6bbm po)ey -0to tune the frequency of a musical instrument. If the tuner hears a beat frequency of 2 Hz, what is oapby-eb) 6m0 the frequency of the instrument?

A. It must be 552 Hz.

B. It must be 548 Hz.

C. It could be either 552 Hz or 548 Hz.

D. It is neither 552 Hz or 548 Hz.

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

71#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The wavelengths of the sounds pb;-lf q.oo; mrroduced by two horns are 6 m and 7 m respectively. What beat frequency is heard when the horns are sounded on a day when the velocity of sol oo;;q .mfbr-und is 340 m/s?

A. $5 \; Hz$

B. $6 \; Hz$

C. $7 \; Hz$

D. $8 \; Hz$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

72#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The corresponding violin strings on tw4*cm 7sqjx2f654 ip1ucvlw nao violins in an orchestra are found to produce a bcpcx6v m 4n2w7 41uailf* sq5jeat frequency of 2 Hz when a frequency of 660 Hz is played. What percentage change in the tension of one of the strings would bring them to the same frequency?

A. 0.2%

B. 0.4%

C. 0.6%

D. 0.8%

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

73#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

An observer approaches a stationary 1000-Hz sound sow(gq-55cyz *dysp2 lkurce at twice the speed of sound. The observer hears a frequency ofyzcp5w(g*s k yq25 l-d

A. 4000 Hz.

B. 2000 Hz.

C. 500 Hz.

D. none of the above

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

74#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A sound source (normal frequency of 1000 Hzu eke-om 3c8)a) approaches a stationary observer ate-eaukm )c8o3 one-half the speed of sound. The observer hears a frequency of

A. 2000 Hz.

B. 500 Hz.

C. 1500 Hz.

D. none of the above

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

75#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A sound has a frequency of 1000 Hz. If a listenerajuv8t+ gcf 2e68. tdsy q/6st moves with a speed of 30 m/s away from the source, what is the frequency heard by the ofsc ta+ yj6 tu/gq68t ve.2ds8bserver? (The sound speed is 340 m/s.)

A. $912 \; Hz$

B. $919 \; Hz$

C. $1000 \; Hz$

D. $1090 \; Hz$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

76#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A police car has an 80ai d41f.umih*;nw s* d0-Hz siren. It is traveling at 35 m/s on a day when the speed of sound through air is 340 m/s. The car approaches a*;s.i umdd n 4wh*fa1ind passes an observer who is standing along the roadside. What change of frequency does the observer hear?

A. zero

B. $82 \; HZ$

C. $166 \; Hz$

D. $249 \; Hz$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

77#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

What is the frequency heard by a sta 0m52lf1 yzkxrtionary observer when a train approaches with a speed of 30 m/s. The frequenr1y 0mz 2klf5xcy of the train horn is 600 Hz and the speed of sound is 340 m/s.

A. $551 \; Hz$

B. $600 \; Hz$

C. $653 \; Hz$

D. $658 \; Hz$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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/h. The train bl5s sem-hhu 1m3ows its 400-Hz whistle. Take the speehh m3 sume1-5sd of sound to be 340 m/s. What frequency do you hear?

A. $444 \; Hz$

B. $439 \; Hz$

C. $364 \; Hz$

D. $361 \; Hz$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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 station:1gcivl q k+,np87qv rary train. The train blows its 400-Hz whistle. Take the speed of sound to be 340 m/s. What frequency do 7kq: pg+8r qn,ilvvc1you hear?

A. $444 \; Hz$

B. $439 \; Hz$

C. $364 \; Hz$

D. $361 \; Hz$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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. Then 5d5qc*ptc)+ qdi)ev train blows its 400-Hz whistle. Take the speed of sound to be 340 m/s. What frequencyic+))d5 n*qqtd p5cev do you hear?

A. $444 \; Hz$

B. $439 \; Hz$

C. $364 \; Hz$

D. $361 \; Hz$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

81#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A train is traveling 51l fuuypccum56v :m55 hlvq6away from you at 120 km/h. It blows its whistle, and you hear a tone u6ul y5cq55vvl5uch6:f m m 1pof 400 Hz. Take the speed of sound to be 340 m/s. What is the actual frequency of the whistle?

A. $444 \; Hz$

B. $439 \; Hz$

C. $364 \; Hz$

D. $361 \; Hz$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信skysky1258，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力

标记此题

82#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The frequency of a traina+c 4babq/ks3as , mguz+puvs.e- )0q horn is 500 Hz. Assume the speed of sound in air is 340 m/s. What is the frequency heard by an observer if the observer is moving awa3z cbu 0,a uqekqs-p/+a4bg+s vm)a. sy from the train with a speed of 30.0 m/s?

A. $500 \; Hz$

B. $456 \; Hz$

C. $548 \; Hz$

D. none of the above

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

83#

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 speed9en mxe-kgmm//9 0(ogc1ofcv of sound in air is 340 0c9nxmckmo/e mo9vg1/g e (- fm/s. What is the frequency heard by an observer if the observer is approaching the train with a speed of 30.0 m/s?

A. $456 \; Hz$

B. $500 \; Hz$

C. $544 \; Hz$

D. none of the above

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

84#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Sonar is used to determine the zemjd4i )2ps) speed of 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 obp2dmj ez 4is))ject moving?

A. 6.9 m/s

B. 8.4 m/s

C. 331 m/s

D. 347 m/s

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

85#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The half angle of the conical shock wave prod-;5shwb vphm)uced by a supersonic aircraft is $60^{\circ}$. What is the Mach number of the aircraft?

A. 0.87

B. 1.2

C. 1.7

D. 2.0

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

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;of0p1t owxv b j.h(d: of the conical shock wave formf: vpj xbdo.0;oth1w(ed?

A. $30^{\circ}$

B. $36^{\circ}$

C. $44^{\circ}$

D. $46^{\circ}$

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

标记此题

87#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The Concord airplane flies from the Unitdsq.wfwcp(7e)x d;w4ed States to Europe with a Mach number of 1.05 where the xw 4e.(; dpc7qsd) wwfair temperature is $5.0 \; ^{\circ}C$. What is the speed of the plane?

A. 334 m/s

B. 337 m/s

C. 351 m/s

D. 359 m/s

绑定到本题的附件链接:
绑定到本题的上传图片:

参考答案:

进入本题讨论区，参与讨论

账号		自动登录	找回密码
密码			立即注册

网页聊天 (离线可收发)

加微信咨询 (申请一对一课程辅导，加本站学习交流群）

电话咨询：

发帖咨询：

查看帮助：

未使用图片

本次作答已使用

1	2	3	4	5	6	7	8	9	10
11	12	13	14	15	16	17	18	19	20
21	22	23	24	25	26	27	28	29	30
31	32	33	34	35	36	37	38	39	40
41	42	43	44	45	46	47	48	49	50
51	52	53	54	55	56	57	58	59	60
61	62	63	64	65	66	67	68	69	70
71	72	73	74	75	76	77	78	79	80
81	82	83	84	85	86	87

1	2	3	4	5	6	7	8	9	10
11	12	13	14	15	16	17	18	19	20
21	22	23	24	25	26	27	28	29	30
31	32	33	34	35	36	37	38	39	40
41	42	43	44	45	46	47	48	49	50
51	52	53	54	55	56	57	58	59	60
61	62	63	64	65	66	67	68	69	70
71	72	73	74	75	76	77	78	79	80
81	82	83	84	85	86	87

1	2	3	4	5	6	7	8	9	10
11	12	13	14	15	16	17	18	19	20
21	22	23	24	25	26	27	28	29	30
31	32	33	34	35	36	37	38	39	40
41	42	43	44	45	46	47	48	49	50
51	52	53	54	55	56	57	58	59	60
61	62	63	64	65	66	67	68	69	70
71	72	73	74	75	76	77	78	79	80
81	82	83	84	85	86	87