Sample problem13-1 a baseball of mass m=0. 143kg falls from h=443m ith v;=0, and its v =42m/s Find the change in the internal energy of the ball and the surrounding air. Solution: system ball air earth F=0=△K+△+△E=0 AU=Ur-U1=0-(mgh)=-621 △K ny 0=126J △E=-△U-△K=495J Ch 13 Energy III: Conservation of energyCh.13 Energy III: Conservation of energy Sample problem13-1 A baseball of mass m=0.143kg falls from h=443m with , and its . vi = 0 U U U mgh J  = f − i = 0 − ( ) = −621 K m v J f 0 126 2 1 2  = − = Fext = 0 K + U + Eint = 0 v m s f =4 2 / Find the change in the internal energy of the ball and the surrounding air. Solution: system = ball + air + Earth. E U K 495J  int = − −  =