A tennis ball which specially consists of mass of .550 kg is rolling upwards with a speed of 28 m/s, if it in reality strikes Tinkerbell who is hovering motionless directly above the ball. Tinkerbell grabs hold of the ball, stops flapping her wings and then rides on the ball till it get to its utmost height. Assume that Tinkerbell consists of a mass of around .870 kg, determine how high above Tinkerbell's original position does she and the ball increase, avoiding air resistance?