To Accelerate or Decelerate a Body Using Easing
1. Right-click a key and choose Edit from the shortcut menu. The Key Editor dialog box opens.
2. In the Interpolation Mode box, select Spline.
3. Click Control. The Spline Control dialog box opens.
4. Select a value in one or both of the boxes under Transition:
◦ Ease to
◦ Ease from
5. Click OK.