1], 1) State and explain D’ Alembert’s principle. (2)

2) A four bar mechanism is subjected to following external forces. The input link AB
makes 600 with horizontal line.

|_Link | Length (mm) | Force | Magnitude (N) | Point of application of Force (r

550 88273.5° 358 mm from A

158/58 327 mm from B
66242° 410 mm from D
(Fixed link)

Determine the shaft torque 72 and its direction on the input link AB for static equilibrium
of the mechanism by principle of virtual work. (8)

IV. The dimen sions of a four link mechanism are AB= 550 mm, BC = 726 mm, CD =
mmand ^] = 1100 71 7. The link AB has an angular velocity of 11 rad/s counter
clockwise and an angular retardation of 28 rad/s? at the instan t when it makes an

angle of 60° with AD, the fixed link. The mass of the links BC and CD is 3.5 kg/m

length. The link AB has a mass of 3.26 kg, the center of whichlie ട at 220mm from A

and amo ment of inertiaof101223kgm 172. Neglecting gravity and friction effects,
determine the Inertia forces on links 2,3,4.