Concept: According to Grashof's law the sum of length of shortest and longest link is compared to the sum of length of adjacent link we get following possibilities. 1. Class 1 mechanism, S + L ≤ P + Q If shortest link fixed double crank mechanism. if any of the adjacent link of the shortest link is fixed then the crank-rocker mechanism. If link opposite to shortest is fixed double rocker mechanism. 2. Class 2 mechanism, S + L ≥ P + Q only a double rocker mechanism is present Calculation: Given: [ alt="F1 Ateeb Madhuri 18.02.2022 D12" src="//storage.googleapis.com/tb-img/production/22/02/F1_Ateeb_Madhuri_18.02.2022_D12.png" style=" width: 210px; height: 244px;"> adjacent link: GF = 3 cm, AB = 3cm longest link AG = 5cm, shortest link FD = 1.5 cm fixed link = GF S + L = FD + AG = 1.5 + 5 = 6.5 cm P + Q = GF + AB = 3 + 3 = 6 thus this condition S + L ≥ P + Q satisfies. It is a grashof chain in which AB, AG and link CDEF is completely rotatable about the link GF.