1. The problem statement, all variables and given/known data A 2.8-m-diameter merry-go-round with rotational inertia 140kg⋅m2 is spinning freely at 0.40rev/s . Four 25-kg children sit suddenly on the edge of the merry-go-round. a) Find the new angular speed. b) Determine the total energy lost to friction between the children and the merry-go-round. 3. The attempt at a solution a) 0.17rev (verified) b) The old mass is 17.85714286kg, old angular speed is 2.513274123 ms-1 The new mass is 117.85714286kg, new angular speed is 1.066237507ms-1 To find the change in energy: 0.5(117.85714286kg)(1.066237507ms-1)2 - 0.5(17.85714286kg)(2.513274123 ms-1)2 The answer is 260j but I'm not getting it.