12-10 할리데이 11판 솔루션 일반물리학 {Swood=50×106[N/m2]ρwood=525[kg/m3]Awood=d2M=430[kg]a=1.9[m]b=2.5[m]g=9.80665[m/s2] \begin{cases} S_{\text{wood}}&=50\times10^6\ut{N/m^2}\\\rho_{\text{wood}}&=525\ut{kg/m^3}\\A_{\text{wood}}&=d^2\\M&=430\ut{kg}\\a&=1.9\ut{m}\\b&=2.5\ut{m}\\g&=9.80665\ut{m/s^2}\end{cases} ⎩⎨⎧SwoodρwoodAwoodMabg=50×106[N/m2]=525[kg/m3]=d2=430[kg]=1.9[m]=2.5[m]=9.80665[m/s2]{ΣFx=0ΣFy=0Στ=0 \begin{cases} \Sigma F_{x}&=0\\\Sigma F_{y}&=0\\\Sigma \tau&=0\\\end{cases} ⎩⎨⎧ΣFxΣFyΣτ=0=0=0{0=Nx−Tx0=Ny−Mg−mg0=aTx−bMg−b2mg \begin{cases} 0&=N_x-T_x\\0&=N_y-Mg-mg\\0&=aT_x-bMg-{b\over2}mg\\\end{cases} ⎩⎨⎧000=Nx−Tx=Ny−Mg−mg=aTx−bMg−2bmg$$ \begin{cases} N_x&={b\over2a}\br{m+2M}g.. 11판/12. 평형과 탄성 2024.06.29
12-9 할리데이 11판 솔루션 일반물리학 put {A:RodB:Box \put \begin{cases} A : \text{Rod}\\B : \text{Box}\\\end{cases} put {A:RodB:Box{L=1.82[m]WA=200[N]WB=300[N]θ=30.0°Tmax=412[N] \begin{cases} L&=1.82\ut{m}\\W_{A}&=200\ut{N}\\W_{B}&=300\ut{N}\\\theta&=30.0\degree\\T_{\max}&=412\ut{N}\\\end{cases} ⎩⎨⎧LWAWBθTmax=1.82[m]=200[N]=300[N]=30.0°=412[N]{ΣFx=0ΣFy=0Στ=0 \begin{cases} \Sigma F_{x}&=0\\\Sigma F_{y}&=0\\\Sigma \tau&=0\\\end{cases} ⎩⎨⎧ΣFxΣFyΣτ=0=0=0{0=Nx−Tcosθ0=Ny−WA−WB+Tsinθ0=−xWB−L2WA+TLsinθ \begin{cases} 0&=N_x-T\cos\theta\\0&=N_y-W_A-W_B+T\sin\theta\\0&=-xW_B-{L\over2}W_A+TL\sin\theta\\\end{cases} ⎩⎨⎧000=Nx−Tcosθ=Ny−WA−WB+Tsinθ=−xWB−2LWA+TLsinθ(a)\ab{a}(a).. 11판/12. 평형과 탄성 2024.06.28
12-8 할리데이 11판 솔루션 일반물리학 (a)\ab{a}(a)com(1)=L2≤L−a1,\com(1)={L\over2}\le L-a_1,com(1)=2L≤L−a1,a1≤L2⋯(1) \begin{aligned}a_1\le{L\over2}\taag1\end{aligned} a1≤2L⋯(1)∴max(a1)=L2\therefore \max(a_1)={L\over2}∴max(a1)=2L(b)\ab{b}(b)com(12)=L+a12≤L−a2,\com(12)={L+a_1\over2}\le L-a_2,com(12)=2L+a1≤L−a2,a2≤L−a12⋯(2) \begin{aligned}a_2\le{L-a_1\over2}\taag2\end{aligned} a2≤2L−a1⋯(2)∴max(a2)=L2(a1=0)\therefore \max(a_2)={L\over2}\\(a_1=0)∴max(a2)=2L(a1=0)(c)\ab{c}(c)com(123)=L+a1+a22≤L−a3,\com(123)={L+a_1+a_2\over2}\le L-a_3,com(123)=2L+a1+a2≤L−a3,a3≤L−a1−a22⋯(3) \begin{aligned}a_3\le{L-a_1-a_2\over2}\taag3\end{aligned} a3≤2L−a1−a2⋯(3)$$\the.. 11판/12. 평형과 탄성 2024.06.26
12-7 할리데이 11판 솔루션 일반물리학 {EIron=200×109[N/m2]m=210[kg]R=1.20[mm]p=2.00[mm]LA=2.50[m]LB=LA+pΔLB=ΔLA−p \begin{cases} E_\text{Iron}&=200\times10^9\ut{N/m^2}\\m&=210\ut{kg}\\R&=1.20\ut{mm}\\p&=2.00\ut{mm}\\L_{A}&=2.50\ut{m}\\L_{B}&=L_{A}+p\\\Delta L_B&=\Delta L_A-p\\\end{cases} ⎩⎨⎧EIronmRpLALBΔLB=200×109[N/m2]=210[kg]=1.20[mm]=2.00[mm]=2.50[m]=LA+p=ΔLA−pFA=E⋅ΔLL,{F\over A}=E\cdot{\Delta L\over L},AF=E⋅LΔL,{0=ΣF=TA+TB−mgTA=E(πR2)⋅ΔLALATB=E(πR2)⋅ΔLBLB \begin{cases} 0&=\Sigma F=T_A+T_B-mg\\T_A&=E (\pi R^2)\cdot{\Delta L_A\over L_A}\\T_B&=E (\pi R^2)\cdot{\Delta L_B\over L_B}\\\end{cases} ⎩⎨⎧0TATB=ΣF=TA+TB−mg=E(πR2)⋅LAΔLA=E(πR2)⋅LBΔLB$$ \begin{aligned}\Delta L_A&=\frac{{.. 11판/12. 평형과 탄성 2024.06.25
12-6 할리데이 11판 솔루션 일반물리학 {mA=11.0[kg]θ=30.0°mB=7.00[kg]g=9.80665[m/s2] \begin{cases} m_A&=11.0\ut{kg}\\\theta&=30.0\degree\\m_B&=7.00\ut{kg}\\g&=9.80665\ut{m/s^2}\end{cases} ⎩⎨⎧mAθmBg=11.0[kg]=30.0°=7.00[kg]=9.80665[m/s2]TA=mAgsinθ,T_A=m_Ag\sin\theta,TA=mAgsinθ,T⃗A=−mAgsinθcosθi^−mBgsin2θj^=−113g4i^−11g4j^⋯(1) \begin{aligned}\vec T_A&=-m_Ag\sin\theta\cos\theta\i-m_Bg\sin^2\theta\j\\&=-{11\sqrt3g\over4}\i-{11g\over4}\j\taag1\\\end{aligned} TA=−mAgsinθcosθi^−mBgsin2θj^=−4113gi^−411gj^⋯(1)TB=mBg,T_B=m_Bg,TB=mBg,T⃗B=−mBgj^=−7gj^⋯(2) \begin{aligned}\vec T_B&=-m_Bg\j\\&=-7g\j\taag2\\\end{aligned} TB=−mBgj^=−7gj^⋯(2)$$ \begin{aligned}\vec T_S&=-\br{\vec T_A+\vec T_B.. 11판/12. 평형과 탄성 2024.06.25
12-5 할리데이 11판 솔루션 일반물리학 {mg=413[N] \begin{cases} mg&=413\ut{N}\\\end{cases} {mg=413[N]{ΣFx=0ΣFy=0Στ=0 \begin{cases} \Sigma F_x&=0\\\Sigma F_y&=0\\\Sigma \tau&=0\\\end{cases} ⎩⎨⎧ΣFxΣFyΣτ=0=0=0{0=Nx−Tsinθ0=Ny+Tcosθ−mg0=mgLsin(2θ)−TLsinθ \begin{cases} 0&=N_x-T\sin\theta\\0&=N_y+T\cos\theta-mg\\0&=mgL\sin\br{2\theta}-TL\sin\theta\\\end{cases} ⎩⎨⎧000=Nx−Tsinθ=Ny+Tcosθ−mg=mgLsin(2θ)−TLsinθ(a)\ab{a}(a)T=2mgcosθ=4133[N]≈715.3369835259463[N]≈715[N] \begin{aligned}T&=2 mg \cos\theta\\&=413\sqrt3\ut{N}\\&\approx 715.3369835259463\ut{N}\\&\approx 715\ut{N}\\\end{aligned} T=2mgcosθ=4133[N]≈715.3369835259463[N]≈715[N](b)\ab{b}(b)$$ \begin{aligned.. 11판/12. 평형과 탄성 2024.06.25
12-4 할리데이 11판 솔루션 일반물리학 (모든 블록의 y축 두께는 문제의 결론에 영향을 주지 않으므로 무시합니다.) (a)\ab{a}(a) put {T:TopL:Middle LeftR:Middle RightB:Bottoml:length \put \begin{cases} T : \text{Top}\\ L : \text{Middle Left}\\ R : \text{Middle Right}\\ B : \text{Bottom}\\ l : \text{length} \end{cases} put ⎩⎨⎧T:TopL:Middle LeftR:Middle RightB:Bottoml:length {ΣFT=0=NT−mgΣFL=0=NL−NT−mgΣFR=0=NR−mgΣFB=0=NB−NL−NR−mg \begin{cases} \Sigma F_T&=0=N_T-mg\\ \Sigma F_{L}&=0=N_{L}-N_T-mg\\ \Sigma F_{R}&=0=N_{R}-mg\\ \Sigma F_B&=0=N_B-N_L-N_R-mg\\ \end{cases} ⎩⎨⎧ΣFTΣFLΣFRΣFB=0=NT−mg=0=NL−NT−mg=0=NR−mg=0=NB−NL−NR−mg $$ \begin{cases} N_T&=mg\\ N_{L}&=2mg\\ N_{R}&=mg\\ N_B&=.. 11판/12. 평형과 탄성 2024.06.25
12-3 할리데이 11판 솔루션 일반물리학 {mA=85[kg]mB=10[kg]M=Σm=95[kg] \begin{cases} m_A&=85\ut{kg}\\m_B&=10\ut{kg}\\M&=\Sigma m= 95\ut{kg}\\\end{cases} ⎩⎨⎧mAmBM=85[kg]=10[kg]=Σm=95[kg]{ΣFx=0ΣFy=0ΣτD=0 \begin{cases} \Sigma F_{x}&=0\\\Sigma F_{y}&=0\\\Sigma \tau_{D}&=0\\\end{cases} ⎩⎨⎧ΣFxΣFyΣτD=0=0=0{0=NC−fD0=ND−Mg0=(xAD)mAg+(xBD)mBg−(yCD)NC \begin{cases} 0&=N_C-f_D\\0&=N_D-Mg\\0&=\br{x_{AD}}m_Ag+\br{x_{BD}}m_Bg-\br{y_{CD}}N_C\\\end{cases} ⎩⎨⎧000=NC−fD=ND−Mg=(xAD)mAg+(xBD)mBg−(yCD)NC$$ \begin{cases} x_{AD}&={L_{AD}\over L_{CD}}x_{OD}\\x_{BD}&={1\over 2}x_{OD}\\y_{CD}&=\sqrt{{L_{CD}}^2-{x_{OD}}^2}\\\end.. 11판/12. 평형과 탄성 2024.06.18
12-2 할리데이 11판 솔루션 일반물리학 {m=6.40[kg]g=9.80665[m/s2] \begin{cases} m&=6.40\ut{kg}\\g&=9.80665\ut{m/s^2}\\\end{cases} {mg=6.40[kg]=9.80665[m/s2]{F=T1T2=2T1T3=2T20=T1+T2+T3−mgT=2T3 \begin{cases} F&=T_1\\T_2&=2T_1\\T_3&=2T_2\\0&=T_1+T_2+T_3-mg\\T&=2T_3\\\end{cases} ⎩⎨⎧FT2T30T=T1=2T1=2T2=T1+T2+T3−mg=2T3T=87mg=71.72864[N]≈71.7[N] \begin{aligned}T&={8\over7}mg\\&=71.72864\ut{N}\\&\approx 71.7\ut{N}\\\end{aligned} T=78mg=71.72864[N]≈71.7[N] 11판/12. 평형과 탄성 2024.06.17
12-1 할리데이 11판 솔루션 일반물리학 {mAg=32[N]mBg=45[N]ϕ=35° \begin{cases} m_Ag&=32\ut{N}\\m_Bg&=45\ut{N}\\\phi&=35\degree\\\end{cases} ⎩⎨⎧mAgmBgϕ=32[N]=45[N]=35°{ΣF⃗A=0ΣF⃗B=0 \begin{cases} \Sigma \vec F_A&=0\\\Sigma \vec F_B&=0\\\end{cases} {ΣFAΣFB=0=0{ΣFAx=0ΣFBx=0ΣFAy=0ΣFBy=0 \begin{cases} \Sigma F_{Ax}&=0\\\Sigma F_{Bx}&=0\\\Sigma F_{Ay}&=0\\\Sigma F_{By}&=0\\\end{cases} ⎩⎨⎧ΣFAxΣFBxΣFAyΣFBy=0=0=0=0{0=T2−T1sinϕ0=−T2+T3sinθ0=T1cosϕ−mAg0=T3cosθ−mBg \begin{cases} 0&=T_2-T_1\sin\phi\\0&=-T_2+T_3\sin\theta\\0&=T_1\cos\phi-m_Ag\\0&=T_3\cos\theta-m_Bg\\\end{cases} ⎩⎨⎧0000=T2−T1sinϕ=−T2+T3sinθ=T1cosϕ−mAg=T3cosθ−mBg(a)\ab{a}(a)$$ \begin{aligne.. 11판/12. 평형과 탄성 2024.06.17