On page 7 of this white paper it is stated:
The linear interpolation can be modified somewhat by adding AccelerationRatio and DecelerationRatio properties to the animation. These attributes essentially create three linear interpolations for the entire animation in order to
modify the starting and stopping speeds. For example, a designer would use these attributes to have an object gradually pick up speed or stop suddenly. Unfortunately, Silverlight does not implement these two attributes, but the effect can be duplicated using
keyframe animations with linear interpolation.
How exactly would the effect be duplicated with keyframes and linear interpolation?