A light spring having a force constant of 139N/m is used to pull a 9.60kg sled on a horizontal ice rink. The coefficient of kinetic friction between the sled and the ice is 0.200. The sled has an acceleration of 2.40m/s^2 . A)Calculate the net upward force on her at the moment the spring reaches its greatest compression. B) Calculate her upward acceleration, in g’s at that moment.