Determine the reaction forces at the joints and the external torque applied to input link 2 of the four-bar linkage in the posture shown. For the constant angular velocity ω2 = 200kˆ rad/s, the known kinematics are α3 = −6 500kˆ rad/s2, α4 = −240kˆ rad/s2, AG3 = −3 160ˆi + 262ˆj ft/s2, and AG4 = −800ˆi −

2 110ˆj ft/s2. The weights and mass moments of inertia of the links are w3 = 2.65 lb, w4 = 6.72 lb, IG2 = 0.023 9 in ·lb ·s2, IG3 = 0.060 6 in ·lb ·s2, and IG4 = 0.531 in · lb ·s2.

Figure P12.4 RAO2 = 2 in, RO4O2 = 13 in, RBA = 17 in, RBO4 = 8 in, and RG4O4 = 4 in.