11판/12. 평형과 탄성

12-12 할리데이 11판 솔루션 일반물리학

짱세디럭스 2024. 6. 29. 13:50
{θ1=40° \begin{cases} \theta_1&=40\degree\\ \end{cases} {ΣFx=0ΣFy=0 \begin{cases} \Sigma F_{x}&=0\\ \Sigma F_{y}&=0\\ \end{cases} {0=T1cosθ1+T2cosθ20=T1sinθ1+T2sinθ2mg \begin{cases} 0&=-T_1\cos\theta_1+T_2\cos\theta_2\\ 0&=T_1\sin\theta_1+T_2\sin\theta_2-mg\\ \end{cases} T2=mgcosθ1sin(θ1+θ2) T_2={mg\cos\theta_1\over\sin\br{\theta_1+\theta_2}} (a)\ab{a} min(T2),sin(θ1+θ2)=1θ1+θ2=90°θ2=50° \begin{aligned} \min (T_2),\\ {\sin\br{\theta_1+\theta_2}}&=1\\ \theta_1+\theta_2&=90\degree\\ \theta_2&=50\degree\\ \end{aligned} (b)\ab{b} T2=cosθ1sin(θ1+θ2)mg=cos40°mg0.766044443118978mg0.77mg \begin{aligned} T_2 &={\cos\theta_1\over\sin\br{\theta_1+\theta_2}}mg\\ &=\cos40\degree mg\\ &\approx 0.766044443118978 mg \\ &\approx 0.77 mg \\ \end{aligned}