Project ForgeFor a four-bar linkage ABCD (A and D fixed pivots on the ground, AB and CD both vertical in the configuration shown), the angular velocity of link AB is 1 rad/s. The length of link CD is 1.5 times the length of link AB. In the configuration shown, the angular velocity of link CD in rad/s is
- A3
- B3/2
- C1
- 2/3
Explanation
Since AB and CD are both vertical at this instant, VB (perpendicular to AB) and VC (perpendicular to CD) are both purely horizontal. The rigid coupler BC cannot stretch, so (VC-VB)·(C-B)=0; since both velocities have only a horizontal component, this forces their horizontal components to be equal: ωAB·AB = ωCD·CD. So ωCD = ωAB·(AB/CD) = 1×(1/1.5) = 2/3 rad/s.
Source: GATE ME 2011 (2011)
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