[问答题]
(a) What minimum for.oi.f hh+yr k(/8ujx6) pvwc l1lw (rqce F is needed to lift the piano (mass M ) using the pulley aq pjruw8/clx)6lv 1( wpparatus shown in
Fig. 4-60? (b) Determine the tension in each section of rope: $F_{\mathrm{T} 1}, F_{\mathrm{T} 2}, F_{\mathrm{T} 3} $, and $ F_{\mathrm{T} 4}$ ,
