A block goes on a wedge which in turns goes on a horizontal table, as given in figure. The wedge angle is Φ.

As long as the wedge is in met with table, we have the trivial constraints that the vertical acceleration of the wedge is zero. To find the constraint, let x be the horizontal co-ordinate

of the end of the wedge and let y and x be the horizontal and vertical coordinate of the block as given then

                (x -X) = (h - y) cot Φ

Even if the friction among the block and wedge affect their acceleration, above relation is remains as long as they are in contact.