Cov nthwv dej transverse - teeb meem thiab kev daws teeb meem

1. Qhov nrug ntawm ob lub qhov dej ntawm cov nthwv dej yog 20 m. Ib yam khoom ntab saum dej kom nws paub txog kev co. Yog tias lub sijhawm mus ncig ib qho kev co yog 4 vib nas this, ces qhov ceev ntawm nthwv dej yog .... m/s

A. 20

B. 15

C. 10

D. 5

Paub:

Qhov ntev ntawm nthwv dej (λ) = 20 meters

Lub Sijhawm (T) = 4 vib nas this

Xav tau: Qhov ceev ntawm nthwv dej (v)

Tshuaj:

Cov qauv ntawm qhov ceev ntawm nthwv dej:

v = λ / T = 20 meters / 4 vib nas this = 5 meters / vib nas this

Cov lus teb yog D.

2. Ob lub ntsiab lus A thiab B nyob rau ntawm txoj hlua thiab sib nrug 90 cm ntawm ib leeg. Ntawm txoj hlua kis cov nthwv dej hla , yog li ntawd lub ntsiab lus A nyob rau saum nthwv dej, lub ntsiab lus B nyob rau hauv qab nthwv dej, thiab nruab nrab ntawm lawv, muaj ob lub crests thiab ob lub troughs. Yog tias lub sijhawm nthwv dej yog 0.3 vib nas this, ces qhov nthwv dej kis yog ...

A. 10.8 cm/s

B. 18.0 cm/s

C. 120.0 cm/s

D. 200.0 cm/s

Paub:

Qhov Nrug Deb AB (l) = 90 cm

Lub sijhawm ntawm nthwv dej (T) = 0.3 vib nas this

Zaus ntawm nthwv dej (f) = 1/0.3 vib nas this

Point A yog nyob rau ntawm qhov siab tshaj plaws ntawm nthwv dej thiab point B yog nyob rau ntawm qhov qis tshaj plaws ntawm nthwv dej.

kuj saib Kev sib npaug ntawm lub ntiajteb txawj nqus

Nruab nrab ntawm cov ntsiab lus A thiab B, muaj ob lub crests thiab ob lub troughs.

Xav tau: Qhov ceev ntawm nthwv dej (v = f λ)

Tshuaj:

Cov teeb meem nthwv dej hla thiab kev daws teeb meem 1 Raws li daim duab, tuaj yeem xaus lus tias muaj 2.5 qhov ntev ntawm lub teeb. Qhov nrug ntawm qhov ntev ntawm lub teeb (λ) = 90 cm / 2.5 = 36 cm

Qhov ceev ntawm nthwv dej:

v = f λ = (1/0.3)(36) = 36/0.3 = 120 cm/s.

Cov lus teb yog C.

3. Daim duab hauv qab no qhia txog qhov kev hloov chaw ntawm ib qho chaw hauv ib qho nruab nrab ua ib qho kev ua haujlwm ntawm lub sijhawm thaum nthwv dej hla dhau qhov nruab nrab.

Cov teeb meem nthwv dej hla thiab kev daws teeb meem 2

Yog tias qhov wavelength yog 6 meters, ces qhov ceev ntawm qhov nthwv dej kis mus rau lwm qhov yog ...

A. 3 m/s

B. 6 m/s

C. 8 m/s

D. 12 m/s

Paub:

Muaj ob lub wavelengths raws li daim duab saum toj no.

Qhov nrug ntawm 1 qhov wavelength (λ) = 6 meters / 2 = 3 meters

Lub Sijhawm (T) = 0.5 vib nas this

Xav tau: Qhov ceev ntawm nthwv dej (v)

Tshuaj:

v = f λ = λ / T = 3 meters / 0.5 vib nas this = 6 meters / vib nas this

Cov lus teb yog B.

4. Raws li daim duab hauv qab no, qhov chaw uas muaj qhov sib txawv ntawm theem ¾ nrog qhov chaw A yog ....

A. Taw Qhia B Cov teeb meem nthwv dej hla thiab kev daws teeb meem 3

B. Taw Qhia C

C. Taw Qhia D

D. Taw Qhia E

tshuaj

Point B muaj qhov sib txawv ntawm ¼ λ nrog point A
Point C muaj qhov sib txawv ntawm theem ntawm 2/4 λ lossis 1/2 λ nrog point A
Point D muaj qhov sib txawv ntawm 3/4 λ nrog point A
Point F muaj qhov sib txawv ntawm theem ntawm 5/4 λ nrog point A.
Cov lus teb yog C.

kuj saib Kev sib npaug ntawm qhov ceev ntawm lub kaum sab xis

5. Ntawm ntug dej, muaj ob nplooj qhuav nyob deb li ntawm 60 centimeters. Ob nplooj ntawd txav mus rau saum thiab nqis zoo li saum npoo dej nrog zaus ntawm 2 Hz. Thaum ib nplooj nyob ntawm lub ncov, lwm nplooj nyob ntawm lub qhov dej, thiab nruab nrab ntawm lawv, muaj ib lub ncov thiab ib lub qhov dej. Txheeb xyuas qhov ceev ntawm nthwv dej kis mus.

A. 20 cm/s

B. 30 cm/s

C. 80 cm/s

D. 120 cm/s

Paub:

Qhov nrug ntawm ob nplooj = 60 cm

Zaus (f) = 2 Hz = 2

Xav tau: Qhov ceev ntawm nthwv dej

Tshuaj:

Cov teeb meem nthwv dej hla thiab kev daws teeb meem 4 Nruab nrab ntawm ob nplooj, muaj 1.5 qhov ntev ntawm cov teeb. Qhov nrug ntawm 1 qhov ntev ntawm cov teeb yog (λ) = 60 cm / 1.5 = 40 cm

Kev ceev ntawm nthwv dej (v):

v = f λ = (2 Hz)(40 cm) = 80 cm/ob vib nas this

Cov lus teb yog C.

6. Raws li daim duab hauv qab no, txiav txim siab qhov amplitude, period, frequency, thiab speed ntawm nthwv dej.

Cov teeb meem nthwv dej hla thiab kev daws teeb meem 6

Tshuaj:

Qhov dav (A) = 4 meters

Lub Sijhawm (T) = 6 vib nas this / 3 = 2 vib nas this

Zaus (f) = 1 / T = 1 / 2 = 0.5 hertz

kuj saib Resonance ntawm cov suab nthwv dej - teeb meem thiab kev daws teeb meem

Qhov ntev ntawm nthwv dej (λ) = 24 meters / 3 = 8 meters

Qhov ceev ntawm nthwv dej (v) = f λ = (0.5 hertz) (8 meters) = 4 meters/ob vib nas this los yog

Qhov ceev ntawm nthwv dej (v) = λ / T = 8 meters / 2 vib nas this = 4 meters / vib nas this

Cov lus teb yog D.

7. Ntawm ib txoj hlua uas ntev li 1.2 m thiab hnyav li 200 g, muaj 1.5 lub nthwv dej sinusoidal nrog zaus ntawm 50 Hz. Raws li cov ntaub ntawv no, txiav txim siab lub sijhawm nthwv dej thiab lub zog nruj ntawm txoj hlua.

A. Lub sijhawm = 0.02 vib nas this thiab lub zog nruj = 6.67 N

B. Lub sijhawm = 0.01 vib nas this thiab lub zog nruj = 6.67 N

C. Lub sijhawm = 0.02 vib nas this thiab lub zog nruj = 266.67 N

D. Lub sijhawm = 0.01 vib nas this thiab lub zog nruj = 266.67 N

Paub:

Qhov ntev ntawm txoj hlua (l) = 1.2 meters thiab muaj 1.5 nthwv dej sinusoidal yog li ntawd qhov deb ntawm 1 wavelength (λ) = 1.2 meters / 1.5 = 0.8 meters

Qhov hnyav ntawm txoj hlua (m) = 200 grams = 0.2 kg

Zaus (f) = 50 Hz

Qhov ceev ntawm txoj hlua (µ) = m/l = 0.2 kg / 1.2 meters = (1/6) kg/meter

Xav tau: Lub sijhawm ntawm nthwv dej (T) thiab lub zog nruj ntawm txoj hlua (T)

Tshuaj:

Lub sijhawm ntawm nthwv dej:

T = 1 / f = 1 / 50 Hz = 0.02 vib nas this

Qhov ceev ntawm nthwv dej ntawm txoj hlua:

v = f λ = (50 Hz)(0.8 meters) = 40 meters/ob vib nas this

Lub zog nruj (T):

Cov teeb meem nthwv dej hla thiab kev daws teeb meem 7

Cov lus teb yog C.

Cia ib saib Ncua tseg teb