11판/9. 질량중심과 선운동량

9-44 할리데이 11판 솔루션 일반물리학

짱세디럭스 2024. 4. 25. 18:43
put {m:manc:car\put \begin{cases} m:\text{man}\\ c:\text{car}\\ \end{cases} {mmg=850[N]mcg=1700[N]vci=18.2[m/s]vmc=4.00[m/s] \begin{cases} m_mg&=850\ut{N}\\ m_cg&=1700\ut{N}\\ v_{ci}&=18.2\ut{m/s}\\ v_{m\larr c}&=-4.00\ut{m/s} \end{cases} vmc=vmvc \begin{aligned} v_{m\larr c}&=v_m-v_c \end{aligned} ΔΣp=0,\Delta \Sigma \vec p=0, pi=pmf+pcf\vec p_i=\vec p_{mf}+\vec p_{cf} (mm+mc)vi=mmvm+mcvc(m_m+m_c)v_i=m_mv_m+m_cv_c vc=vimmmc+mmvmc v_c=v_i-\frac{m_m }{m_c+m_m}v_{m\larr c} Δvc=vcvi=mmmc+mmvmc=mmgmcg+mmgvmc=43[m/s]1.3333333333333333[m/s]1.33[m/s] \begin{aligned} \Delta v_c&=v_c-v_i\\ &=-\frac{m_m }{m_c+m_m}v_{m\larr c}\\ &=-\frac{m_m g}{m_cg+m_mg}v_{m\larr c}\\ &=\frac{4}{3}\ut{m/s}\\ &\approx 1.3333333333333333\ut{m/s}\\ &\approx 1.33\ut{m/s}\\ \end{aligned}