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匿名使用者 發問時間: 科學其他:科學 · 7 年前

請念物理或醫科系幫忙解答??

22. Sound wave passes from air to water. Its frequency:

a.increases, whereas its wavelength remains the same

b.decreases, whereas its wavelength remains the same

c.is constant, whereas its wavelength increases

d.is constant, whereas its wavelength decreases

23. The source of sound is moving toward the stationary observer at constant velocity. The frequently heard by a stationary observer behind the moving source is:

a.higher than for the stationary source

b.lower than for the stationary source

c.the same as for the stationary source

d.the same as for the stationary source, but its intensity decreases

24. Two-time increase in the absolute temperature of the gas causes:

a.two-time increase in the average translation kinetic energy of its molecules

b.two-time decrease in the average translation kinetic energy of its molecules

c.four-time increase in the average translation kinetic energy of gas molecules

d.four-time decrease in the average translation kinetic energy of gas molecules

25. The distance between two nodes of the standing wave, propagated in air, is 34 cm (speed of sound in air c=340 m/s). The frequency of the sound wave is:

a.340 Hz b. 500 Hz c. 1000 Hz d. 2000Hz

26. The car of velocity 25 m/s and mass 800 kg decelerates to 0 m/s at 5 s. The work done by the friction force braking the car (see the previous question) was:

a.250 kJ b. 25kJ c. 2.5 kJ d. 0.25 kJ

已更新項目:

漏了 再補充一題 麻煩了~~

Shape of methane molecule results from:

A. Poor electrongetivity of carbon

B. Ionic character of the bonds

C. sp 3次方 hybridisation

D. Formation of metallic bond

E. Formation of the aromatic ring

2 個已更新項目:

只要答案就可以囉~~~

3 個已更新項目:

其實沒特定科系 只是可能解答比較正確

13 個解答

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