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we know that
   ω = 2 π f
       = 2 π / T
   given that t = T / 4
   so we get
   ω t = π / 2
   the spring constant will be
   k = 4 π2 m1 /T2
      = 1.97 x 105 N /m
   if φ = π / 2
   the location of block 2 is
   x = xm cos(ωt +φ)
   x = xm cos[(π / 2) + (π/ 2)]
      = - xm
   this means that the 2 is at a turning pointin its motion and also the spring is streched an distance
   0.01 m at this moment
   to get the speed after the collision we usethe momentum conservation
   (4.0 kg) (6.0 m / s) / (6.0 kg) = 4.0 m /s
   so at the end of the impact it has kineticenergy
   (1 / 2) (6.0 kg) (4.0 m / s)2 =....... J and
   potential energy (1 / 2)(1.97 x 105 N/ m) (0.01 m)2 = ......... J
   the total mechanical energy will be
   E = KE + PE
      = ....... J
   the amplitude will be
   X = √[2 (E) / (1.97 x 105 N/ m)]
       = ........ m