L=100см=1м                           T=2π√l\g

                                                   T=2π√1\10

                                                   T=2×3.14×0.3

                                                         T=1.88 или 1.9с

найти период колебаний стержня длиной l=100 см=1м

  T=2пи√l/g =2·3,14√(1/9,81)=2с