Rigid Body Constraint and Wedge Constraint

What is a wedge constraint?
In any wedge constraints problem,for example if two blocks are sliding over each other like this- Sorry for the gap between both of them, they are actually in contact. Block B will slide down and block A will move in forward direction.

What are constraints forces?
Constrained motion results when an object is forced to move in a restricted way. ... Constraint Forces are the forces that the constraining object exerts on the object to make it follow the motional constraints.

What is the constraint equation?
A constraint equation is the definite relation that the unknown variables always maintain between them.

How do you find the constraints in a relation?
Find the constraint relation between a1,a2 and a3.

For finding constraint relation, we must find the relation between displacements of the 3 bodies. Then we will double differentiate both the relations regarding displacement which will give us the constraint relation.