Qhov ceev thiab kev ntab hauv qhov sib npaug - cov teeb meem thiab kev daws teeb meem

Qhov ceev thiab kev ntab hauv qhov sib npaug - cov teeb meem thiab kev daws teeb meem

1. Ib lub thaiv uas muab tso rau hauv ob lub kua uas muaj ntau hom sib txawv. Hauv cov kua A, muaj 0.6 feem ntawm ib yam khoom nyob hauv cov kua. Hauv cov kua B, muaj 0.5 feem ntawm ib yam khoom nyob hauv cov kua. Txheeb xyuas qhov sib piv ntawm qhov ceev ntawm cov kua A rau cov kua B.

Paub:

Qhov ceev ntawm thaiv = x

Ib feem ntawm cov khoom hauv cov kua A = 0.6

Qhov ceev ntawm cov kua A = y

Ib feem ntawm yam khoom hauv cov kua B = 0.5

Qhov ceev ntawm cov kua B = z

Xav tau: Qhov sib piv ntawm qhov ceev ntawm cov kua A rau cov kua B (y: z)

Tshuaj:

Hloov x hauv kab zauv 2 nrog x hauv kab zauv 1:

2. Ib yam khoom muab tso rau hauv cov kua P, 0.5 feem ntawm cov khoom nyob hauv cov kua. Thaum muab cov khoom tso rau hauv cov kua Q, cov khoom nyob hauv cov kua, raws li pom hauv daim duab hauv qab no. Qhov sib piv ntawm qhov ceev ntawm cov kua P rau cov kua Q yog dab tsi?

Paub:

Qhov ceev ntawm yam khoom = x

Ib feem ntawm yam khoom hauv cov kua P = 1/2 = 0.5

Qhov ceev ntawm cov kua P = y

Ib feem ntawm cov khoom hauv cov kua Q = 1

Qhov ceev ntawm cov kua Q = z

Xav tau: Qhov piv ntawm qhov ceev ntawm cov kua P rau cov kua Q (y: z)

Tshuaj:

Hloov x hauv kab zauv 2 nrog x hauv kab zauv 1:

3. Ib tug ntoo uas ntab hauv roj (qhov ceev ntawm roj yog 800 kg/m3 ⁾ . 4/5 ntawm cov ntoo nyob hauv roj . Qhov ceev ntawm cov ntoo yog dab tsi?

Paub:

Qhov ceev ntawm roj (ρ) = 800 kg/m ^-3

Ib feem ntawm ntoo hauv roj = 4/5

Xav tau: Qhov ntom ntawm ntoo

Tshuaj:

Qhov ceev ntawm ntoo yog 640 kg / ^m3.

4. Qhov hnyav ntawm ib lub thaiv yog 50 N. Hauv dej, qhov hnyav ntawm lub thaiv yog 30 N. Yog tias qhov ceev ntawm dej yog 10 ³ kg/m ^-3, qhov ceev ntawm lub thaiv yog dab tsi.

Paub:

Qhov hnyav ntawm lub thaiv hauv huab cua (w) = 50 N

Qhov hnyav ntawm lub thaiv hauv dej (w _dej ) = 30 N

Qhov Ceev ntawm dej (ρ _dej ) = 10 ³ kg/m3 ⁼ 1000 kg/ ^m3

Kev nrawm vim lub ntiajteb txawj nqus (g) = 10 m/s ²

Qhov hnyav ntawm lub thaiv (m) = w/g = 50/10 = 5 kg

Xav tau: Qhov ceev ntawm cov blocks (ρ _blocks )

Tshuaj:

Lub zog buoyant:

F _A = ​​​​w – w _dej = 50 – 30 = 20 N

Qhov ntim ntawm cov blocks hauv dej:

F _A = ​​​​ρ g V

20 = (1000)(10) V

20 = (10,000) V

V = 20/10,000

V = 0.002 ^m3

Qhov ceev ntawm thaiv:

ρ = m/V = 5/0.002 = 2500 kg/m ³

5. Ib lub thaiv ntoo uas muab tso rau hauv dej. 25% ntawm nws cov khoom nyob saum npoo dej thiab 75% nyob hauv dej. Qhov ceev ntawm dej yog 1 g/cm3 ^thiab qhov nrawm vim lub ntiajteb txawj nqus yog 10 m/s2 ^. Txheeb xyuas qhov ceev ntawm cov thaiv.

A. 0.025 kg/ ^m3

B. 0.075 g/ ^cm3

C. 0.250 kg/ ^m3

D. 0.750 g/ ^cm3

Paub:

Ib feem ntawm cov blocks saum npoo dej = 25% = 25/100 = 0.25

Qhov feem ntawm thaiv hauv dej = 75% = 75/100 = 0.75

Qhov ceev ntawm dej (ρ _dej ) = 1 g/cm3 ⁼ 1000 kg/ ^m3

Kev nrawm vim lub ntiajteb txawj nqus = 10 m/s ²

Xav tau: Qhov ceev ntawm cov blocks (ρ _blocks )

Tshuaj:

Qhov ntim ntawm cov blocks hauv dej = qhov sib piv ntawm qhov ceev ntawm cov blocks rau qhov ceev ntawm dej

Cov lus teb yog D.

1. Qhov ceev yog dab tsi, thiab nws txhais li cas los ntawm kev lej?
   • teb: Qhov ceev yog qhov ntsuas ntawm qhov hnyav npaum li cas muaj nyob rau hauv ib qho ntim. Kev suav lej, nws tau txhais tias yog qhov ceev =loj / ntim​.
2. Qhov ceev ntawm ib yam khoom txiav txim li cas tias nws yuav ntab los yog tog hauv cov kua dej?
   • teb: Yog tias qhov ceev ntawm ib yam khoom tsawg dua qhov ceev ntawm cov kua dej uas nws nyob hauv, yam khoom ntawd yuav ntab. Ntawm qhov tod tes, yog tias qhov ceev ntawm yam khoom ntawd ntau dua qhov ceev ntawm cov kua dej, nws yuav poob.
3. Lub hauv paus ntsiab lus tom qab kev ntab lossis kev poob ntawm ib yam khoom hauv cov kua dej yog dab tsi?
   • teb: Lub hauv paus ntsiab lus yog Archimedes' Principle, uas hais tias lub cev raug raus rau hauv qhov kev paub txog kua dej ntawm lub zog nce mus rau saum ntuj sib npaug rau qhov hnyav ntawm cov kua dej uas nws hloov chaw.
4. Yog tias ib lub voos xwmfab dej khov ntab hauv dej nrog ib feem ntawm nws nyob saum dej, qhov no qhia txog qhov sib piv ntawm cov dej khov thiab dej li cas?
   • teb: Qhov no qhia tau hais tias qhov ceev ntawm dej khov tsawg dua qhov ceev ntawm dej. Yog vim li cas lub voos dej khov thiaj li ntab, thiab tsuas yog ib feem ntawm nws tseem nyob hauv dej kom tshem tawm cov dej uas sib npaug rau lub voos dej khov.
5. Vim li cas cov nkoj hlau hnyav thiaj ntab saum dej thaum tus ntsia hlau me me yuav tog?
   • teb: Qhov ceev ntawm lub nkoj hlau, suav nrog nws cov qhov khoob uas puv nrog cua, tsawg dua qhov ceev ntawm dej. Qhov sib piv, qhov ceev ntawm tus ntsia hlau hlau khov kho yog ntau dua qhov ceev ntawm dej, ua rau nws tog.
6. Lub tswv yim ntawm "neutral buoyancy" txawv li cas ntawm kev ntab lossis kev poob?
   • teb: Qhov nruab nrab ntawm kev ntab dej tshwm sim thaum qhov hnyav ntawm ib yam khoom sib npaug los ntawm lub zog ntab dej, ua rau yam khoom nyob twj ywm hauv cov kua dej yam tsis nce lossis poob.
7. Vim li cas lub balloon helium thiaj li ntab hauv huab cua?
   • teb: Qhov ceev ntawm helium tsawg dua li qhov ceev ntawm huab cua. Yog li ntawd, qhov hnyav ntawm lub npas helium (suav nrog cov khoom siv npas thiab helium sab hauv) tsawg dua li qhov hnyav ntawm huab cua uas nws hloov chaw, ua rau nws ntab.
8. Yuav ua li cas rau qhov ceev ntawm ib yam khoom thaum nws raug nias rau hauv ib qho me me thaum nws qhov hnyav tseem ruaj khov?
   • teb: Qhov ceev yuav nce ntxiv vim tias qhov ceev yog txhais tias yog pawg faib los ntawm qhov ntim. Yog tias qhov ntim txo qis thiab pawg tseem ruaj khov, qhov piv (qhov ceev) yuav nce ntxiv.
9. Salinity cuam tshuam li cas rau qhov ceev ntawm dej?
   • teb: Qhov ua kom dej ntsev ntau ntxiv (piv txwv li, ntxiv ntsev ntau ntxiv) yuav ua rau nws ntom zuj zus. Qhov no yog vim li cas tej yam khoom feem ntau ntab tau yooj yim dua hauv dej ntsev (xws li Hiav Txwv Tuag) piv rau dej qab zib.
10. Yog tias ib yam khoom ntab hauv qhov sib npaug hauv cov kua dej, lub zog ntab thiab lub zog gravitational ntawm yam khoom sib piv li cas?

• teb: Thaum ib yam khoom ntab hauv qhov sib npaug, lub zog ntab (lub zog nce mus rau saum ntuj vim yog cov kua dej) yog sib npaug zos thiab sib txawv rau lub zog gravitational (qhov hnyav) uas ua rau yam khoom.