“…Example 9 We implement (41) for a frequently proposed system ( [16], [2]), consisting in two material points (P 1 , M 1 ) and (P 2 , M 2 ) on a plane whose velocities are both orthogonal to the line joining P 1 with P 2 . The linear kinematic constraints for P 1 ≡ (x 1 , y 1 ) and P 2 ≡ (x 2 , y 2 ) are ẋ1 (x 2 − x 1 ) + ẏ1 (y 2 − y 1 ) = 0, ẋ2 (x 2 − x 1 ) + ẏ2 (y 2 − y 1 ) = 0.…”