Piv txwv ntawm cov lus nug ntawm Inclined Plane

9 Piv txwv ntawm Cov Lus Nug Txog Lub Dav Hlau Inclined

Kawm cov ntaub ntawv hais txog Newton txoj cai , lub zog ib txwm muaj thiab lub zog sib txhuam kom nkag siab zoo dua txog kev sib tham ntawm lo lus nug no.

1. Ib lub thaiv 5 kg raug tso tawm rau ntawm ib lub dav hlau du raws li pom hauv daim duab! (g = 10 ms ⁻² thiab tg 37 ^o = 3/4). Qhov kev nrawm ntawm lub thaiv yog...

A. 4,5 ms^-2

B. 6,0 ms ⁻²

C. 7,5 ms ⁻²

D. 8,0 ms ⁻²

E. 10,0 ms ⁻²

Kev Sib Tham

Nws paub tias:

m = 5 kg, g = 10 m/s ²

w = mg = (5)(10) = 50 N

qhov ntev ntawm sab hauv qab = 4

qhov ntev ntawm sab ntsug = 3

Vim tias sab hauv qab = 4 thiab sab ntsug = 3 ces sab hypotenuse = 5. Koj tuaj yeem ua pov thawj nws siv tus qauv Pythagorean.

Lo lus nug: kev ua kom nrawm ntawm lub thaiv (a)?

Lus teb:

Lub zog uas ua rau lub thaiv txav mus los yog w _x . Lub dav hlau inclined yog du yog li ntawd tsis muaj kev sib txhuam.

w_x = w kev txhaum θ = (w)(sab ntsug / hypotenuse)

w _x = (50)(3/5)

w _x = 30 Newton

Qhov kev nrawm (a) ntawm lub block yog dab tsi?

Σ F = ma

w _x = ma

30 = (5) ib

ib = 30 / 5

a = 6 m/s ²

Cov lus teb yog B.

2. Saib daim duab! Thaum xub thawj, ib lub thaiv raug so, tom qab ntawd rub nrog lub zog F mus rau saum toj sib luag rau lub dav hlau inclined. Qhov hnyav ntawm lub thaiv yog 8 kg, tus coefficient ntawm kev sib txhuam µs ₌ 0,5 thiab θ = 45 ^o . Rau lub thaiv kom txav mus rau saum toj, lub zog F yuav tsum yog….

A. 40 N

B. 60 N

C. 60√2 N

D. 80 N

E. 80√2 N

Kev Sib Tham

Nws yog paub tias :

Cov coefficient ntawm kev sib txhuam zoo li qub (µs ₎ = 0,5

Lub kaum sab xis (θ) = 45 ^o

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

Qhov hnyav ntawm lub thaiv (m) = 8 kilograms

Qhov hnyav ntawm lub thaiv (w) = mg = (8 kg) (10 m/s ² ) = 80 kg m/s ² = 80 Newtons

Lus Nug : Qhov loj ntawm lub zog F kom lub block txav mus rau sab saud

Lus teb :

Lub thaiv yuav txav mus rau sab saud yog tias F ≥ wx ₊ fs_.

Lub Cheebtsam ntawm lub ntiajteb txawj nqus sib luag rau lub dav hlau inclined :

w _x = w sin θ = (80)(sin 45) = (80)(0,5√2) = 40√2

Lub Cheebtsam ntawm lub ntiajteb txawj nqus perpendicular rau lub dav hlau inclined :

w _y = w cos θ = (80)(cos 45) = (80)(0,5√2) = 40√2

Lub zog ib txwm muaj :

N = w ₌ 40√2

Lub zog sib txhuam zoo li qub :

f _s = µs _N = (0,5)(40√2) = 20√2

Qhov loj ntawm lub zog F kom lub block txav mus rau sab saud :

F ≥ w _x + f _s

F ≥ 40√2 + 20√2

F ≥ 60√2 Newtons

Cov lus teb yog C.

3. Muab ib lub thaiv uas hnyav 8 kg tso rau ntawm ib lub dav hlau uas nkhaus raws li pom hauv daim duab hauv qab no. Lub zog sab nraud tsawg kawg nkaus uas yuav tsum tau los tiv thaiv lub thaiv kom tsis txhob swb mus rau hauv qab yog… (sin 37 ^o = 0,6, cos 37 ^o = 0,8, g = 10 ms ^-2 , µk ₌ 0,1)

A. 6,4 N

B. 4,6 N

C. 48,5 N

D. 54,4 N

Sab Hnub Tuaj 68,8 N

Kev Sib Tham

Nws yog paub tias :

Qhov hnyav ntawm lub thaiv (m) = 8 kg

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

Qhov hnyav ntawm lub thaiv (w) = mg = (8)(10) = 80 Newton

Sin 37 ^o = 0,6

Cos 37 ^o = 0,8

Coefficient ntawm kinetic sib txhuam (µk ₎ = 0,1

N = _wy = w cos 37 ^o = (80)(0,8) = 64 Newtons

Lo lus nug : Lub zog sab nraud tsawg kawg nkaus (F) xav tau los txhawb lub thaiv kom lub thaiv tsis txhob swb.

Jawb :

Lub thaiv tsis swb rau hauv qab yog tias F = w _x

Lub Cheebtsam ntawm lub ntiajteb txawj nqus sib luag rau lub dav hlau inclined :

w _x = w sin θ = (80)(sin 37) = (80)(0,6) = 48

f _k = µ _k N = (0,1)(64) = 6,4

Lub zog tsawg kawg nkaus F kom lub thaiv tsis txhob swb mus rau hauv av :

F + fk _– wx ₌ 0

F = w _x – f _k = 48 – 6,4 = 41,6 Newtons

4. Ib yam khoom uas muaj qhov hnyav li 5,0 kg raug rub nrog txoj hlua mus rau saum ib lub dav hlau uas nkhaus los ntawm lub zog ntawm 71 N (g = 10 m s ^-2 , sin 37 ^o = 0,6, cos 37 ^o = 0,8). Yog tias qhov coefficient ntawm kev sib txhuam ntawm yam khoom thiab lub dav hlau yog 0,4, qhov kev nrawm uas yam khoom ntawd ntsib yog…

A. 0,5 ms^-2

B. 2 ms ^-2

C. 2,5 ms ^-2

D. 3 ms ^-2

E. 5 ms ^-2

Kev Sib Tham

Nws yog paub tias :

Qhov hnyav ntawm yam khoom (m) = 5 kg

4. 2012/2013 SMA Physics National Exam Cov Lus Nug SA 67 No. 5

Ib yam khoom hnyav 5,0 kg raug rub los ntawm txoj hlua mus rau saum ib lub dav hlau uas nkhaus los ntawm lub zog ntawm 71 N (g = 10 m s ^-2 , sin 37 ^o = 0,6, cos 37 ^o = 0,8). Yog tias qhov coefficient ntawm kev sib txhuam ntawm yam khoom thiab lub dav hlau yog 0,4, qhov kev nrawm uas yam khoom ntawd ntsib yog…

A. 0,5 ms ^-2

B. 2 ms ^-2

C. 2,5 ms ^-2

D. 3 ms ^-2

E. 5 ms ^-2

Kev Sib Tham

Nws yog paub tias :

Qhov hnyav ntawm yam khoom (m) = 5 kg

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

Qhov hnyav ntawm yam khoom (w) = mg = (5)(10) = 50 Newtons

Lub zog F = 71 Newton

Sin 37 ^o = 0,6

Cos 37 ^o = 0,8

Kev sib txhuam ntawm kev sib txhuam = 0,4

Lus Nug : Kev nrawm ntawm yam khoom (a)

Lus teb :

Lub zog tshwm sim

Ua ntej xam lub zog uas tshwm sim rau ntawm yam khoom.

Lub Cheebtsam ntawm lub ntiajteb txawj nqus sib luag rau lub dav hlau inclined :

w _x = w sin θ = (50)(sin 37) = (50)(0,6) = 30

Lub zog ntawm lub ntiajteb txawj nqus perpendicular rau lub dav hlau inclined :

w _y = w cos θ = (50)(cos 37) = (50)(0,8) = 40

Tus qauv ib txwm :

N = wy ₌ 40

Lub zog sib txhuam kinetic :

f _k = µk _N = (0,4)(40) = 16

Lub zog tshwm sim ua rau ntawm lub dav hlau inclined:

∑ F = F – w _x – f _k = 71 – 30 – 16 = 25 Newtons

Kev nrawm ntawm ib yam khoom

Qhov kev nrawm ntawm ib yam khoom yog xam los ntawm kev siv Newton txoj cai thib ob:

a = ∑F / m = 25 / 5 = 5 m/s ²

Cov lus teb yog yog E.

5.
Saib daim duab! Ib lub thaiv thaum xub thawj tsis txav, ces rub mus rau saum nrog lub zog F sib luag rau lub dav hlau uas nkhaus. Qhov hnyav ntawm lub thaiv yog 8 kg, qhov sib txhuam coefficient yog µ_s = 0,5 thiab θ = 45^oYuav kom lub block txav mus rau sab saud, lub zog F yuav tsum yog….

A. 40 N
B. 60 N
C. 60√2 N
D. 80 N
E. 80√2 N

Kev Sib Tham
Nws yog paub :
Tus lej sib piv kev sib txhuam zoo li qub (µ_s= 0,5 TZS
Lub kaum sab xis (θ) = 45^o
Kev nrawm vim lub ntiajteb txawj nqus (g) = 10 m/s²
Qhov hnyav ntawm lub thaiv (m) = 8 kilograms
Qhov hnyav ntawm lub thaiv (w) = mg = (8 kg) (10 m/s)²) = 80 kg m/s² = 80 Newtons
Nug : Qhov loj ntawm lub zog F kom lub block txav mus rau sab saud
Jawb :

Lub thaiv sab xis yuav txav mus rau sab saud yog tias F ≥ w_x + f_s.
Lub Cheebtsam ntawm lub ntiajteb txawj nqus sib luag rau lub dav hlau inclined :
w_x W sin θ = (80)(sin 45) = (80)(0,5√2) = 40√2
Lub Cheebtsam ntawm lub ntiajteb txawj nqus perpendicular rau lub dav hlau inclined :
w_y = w cos θ = (80)(cos 45) = (80)(0,5√2) = 40√2
Lub zog ib txwm muaj :
N = w_y = 40√2
Lub zog sib txhuam zoo li qub :
f_s = µ_s N = (0,5)(40√2) = 20√2
Qhov loj ntawm lub zog F kom lub block txav mus rau sab saud :
F ≥ w_x + f_s
F ≥ 40√2 + 20√2
F ≥ 60√2 Newtons
Cov lus teb yog C.

6.
Ib lub thaiv uas muaj qhov hnyav ntawm 8 kg raug muab tso rau ntawm ib lub dav hlau uas nkhaus raws li pom hauv daim duab hauv qab no. Lub zog sab nraud tsawg kawg nkaus uas xav tau los tiv thaiv lub thaiv kom tsis txhob swb mus rau hauv qab yog… (sin 37^o = 0,6, cos37^o = 0,8, g = 10 ms^-2, µ_k = 0,1)

A. 6,4 N
B. 4,6 N
C. 48,5 N
D. 54,4 N
Sab Hnub Tuaj 68,8 N

Kev Sib Tham
Nws yog paub :
Qhov hnyav ntawm lub thaiv (m) = 8 kg
Kev nrawm vim lub ntiajteb txawj nqus (g) = 10 m/s²
Qhov hnyav ntawm lub thaiv (w) = mg = (8)(10) = 80 Newton
Kev txhaum 37^o = 0,6
Kos 37^o = 0,8
Coefficient ntawm kev sib txhuam kinetic (µ)_k= 0,1 TZS
Nug Lub zog sab nraud tsawg kawg nkaus (F) tuav lub thaiv kom lub thaiv tsis txhob swb mus rau hauv qab
Jawb :
Lub thaiv tsis swb nqes yog tias F = w_x
Lub Cheebtsam ntawm lub ntiajteb txawj nqus sib luag rau lub dav hlau inclined :
w_x = w sin θ = (80)(sin 37) = (80)(0,6) = 48
f_k = µ_k N = (0,1)(64) = 6,4
Lub zog tsawg kawg nkaus F kom lub thaiv tsis txhob swb mus rau hauv av :
F + f_k - w_x = 0
F = w_x - f_k = 48 – 6,4 = 41,6 Newtons

7.
Ib yam khoom uas hnyav 5,0 kg raug rub los ntawm txoj hlua mus rau saum ib lub dav hlau uas nkhaus los ntawm lub zog ntawm 71 N (g = 10 m s).^-2, kev txhaum 37^o = 0,6, cos37^o = 0,8). Yog tias tus coefficient ntawm kev sib txhuam ntawm cov khoom thiab lub dav hlau yog 0,4, qhov kev nrawm uas cov khoom ntsib yog...
A. 0,5 ms^-2
B. 2 ms^-2
C. 2,5 ms^-2
D. 3 ms^-2
E. 5 ms^-2
Kev Sib Tham
Nws yog paub :
Qhov hnyav ntawm yam khoom (m) = 5 kg
Kev nrawm vim lub ntiajteb txawj nqus (g) = 10 m/s²
Qhov hnyav ntawm yam khoom (w) = mg = (5)(10) = 50 Newtons
Lub zog F = 71 Newton
Kev txhaum 37^o = 0,6
Kos 37^o = 0,8
Kev sib txhuam ntawm kev sib txhuam = 0,4
Nug : Kev nrawm ntawm yam khoom (a)
Jawb :
Lub zog tshwm sim
Ua ntej xam lub zog uas tshwm sim rau ntawm yam khoom.
Lub Cheebtsam ntawm lub ntiajteb txawj nqus sib luag rau lub dav hlau inclined :
w_x = w sin θ = (50)(sin 37) = (50)(0,6) = 30
Lub Cheebtsam ntawm lub ntiajteb txawj nqus perpendicular rau lub dav hlau inclined :
w_y = w cos θ = (50)(cos 37) = (50)(0,8) = 40
Lub zog ib txwm muaj :
N = w_y = 40
Lub zog sib txhuam kinetic :
f_k = µ_k N = (0,4)(40) = 16
Lub zog tshwm sim ua rau ntawm lub dav hlau inclined:
∑F = F – w_x - f_k = 71 – 30 – 16 = 25 Newtons
Kev nrawm ntawm ib yam khoom
Qhov kev nrawm ntawm ib yam khoom yog xam los ntawm kev siv Newton txoj cai thib ob:
a = ∑F / m = 25 / 5 = 5 m/s²
Cov lus teb yog yog E.

8. Saib daim duab! Ib lub thaiv thaum xub thawj nyob twj ywm, tom qab ntawd rub nrog lub zog F mus rau saum toj sib luag rau lub dav hlau inclined. Qhov hnyav ntawm lub thaiv yog 2 kg, tus coefficient ntawm static friction = 0,3 thiab lub kaum sab xis = 45 ^o . Rau lub thaiv txav mus rau saum toj, lub zog F yuav tsum yog ... g = 10 m/s ²

Kev Sib Tham
Nws paub tias:
m = 2 kg, g = 10 m/s², = 45^o, μ_s = 0,3
Lo lus nug: Yuav kom lub block txav mus rau sab saud, lub zog F loj npaum li cas?
Lus teb:

Cov Ntaub Ntawv: F = lub zog tensile, w = lub zog gravity, w_x = feem ntawm qhov hnyav ntawm lub thaiv sib luag rau qhov chaw ntawm lub dav hlau inclined, w_y = feem ntawm qhov hnyav ntawm lub thaiv perpendicular rau qhov chaw ntawm lub dav hlau inclined, N = lub zog ib txwm muaj, f_s = lub zog sib txhuam static.

Hauv lo lus nug, tus coefficient ntawm static friction paub, qhov no txhais tau tias qhov chaw ntawm lub dav hlau inclined yog ntxhib kom muaj lub zog frictional uas inhibits qhov kev txav ntawm lub block.
Yuav kom lub block txav mus rau sab saud, lub zog F yuav tsum sib npaug rau w._x +f_s. Cov khoom txav mus rau sab saud thaum F loj dua w_x +f_s.

w = mg = (2)(10) = 20 Newtons
w_x = w sin 45^o = (20)(½ √2) = 10√2 Newtons
w_y = w cos 45^o = (20)(½√2) = 10√2 Newtons
N = w_y = 10√2
f_s = μ_s N = (0,3)(10√2) = 3√2 Newtons

Yog li ntawd lub block yuav txav mus rau sab saud ces:
F = w_x +f_s = 10√2 + 3√2= 13√2 Newtons
Cov lus teb yog C.

9. Ib yam khoom uas muaj qhov hnyav ntawm 2 kg raug muab tso rau ntawm lub dav hlau inclined raws li qhia hauv daim duab hauv qab no. Yog tias qhov coefficient ntawm static friction ntawm lub block thiab lub dav hlau inclined yog 0,2√3 thiab g = 10 ms ^–2 , ces lub zog tshwm sim uas txav lub khoom yog…

Kev Sib Tham
Nws paub tias:
m = 2 kg, g = 10 m/s², = 30^o, μ_s = 0,2√3
Nug: Lub zog uas ua rau ib yam khoom txav mus?

Lus teb:

Kev sib txhuam yeej ib txwm txwv tsis pub ib yam khoom txav mus los, yog li ntawd, qhov kev taw qhia ntawm lub zog sib txhuam yog piav qhia tias yog qhov sib txawv ntawm qhov kev taw qhia ntawm yam khoom txav mus los. Xav tias yam khoom txav mus rau hauv qab, yog li lub zog sib txhuam yog piav qhia tias yog sab saud. Xav tias yam khoom txav mus rau hauv qab vim tias tsis muaj lub zog rub nws mus rau saum toj.
w = mg = (2)(10) = 20 Newtons
w_x = w sin 30^o = (20)( ½ ) = 10 Newtons
w_y = w cos 30^o = (20)( ½ √3) = 10√3 Newtons
N = w_y = 10√3 Newtons
f_s = μ_s N = (0,2√3)(10√3) = (2)(3) = 6 Newtons
Lub zog uas ua rau ib yam khoom txav mus yog:
F = w_x - f_s = 10 – 6 = 4 Newtons
w_x loj dua f_s yog li ntawd, qhov khoom txav mus rau hauv qab, hauv qhov kev taw qhia ntawm w_x.
Cov lus teb yog lawm yog A.

Qhov chaw nug lus:

Cov Lus Nug Txog Kev Xeem Physics Hauv Tebchaws Rau Tsev Kawm Ntawv Theem Siab/Tsev Kawm Ntawv Theem Siab Ua Haujlwm