Question

Common Data Questions: An instantaneous configuration of a four-bar mechanism whose plane is horizontal, is shown in the figure below. At this instant, the angular velocity and angular acceleration of link $O_{2}A$ are $\omega =8$ rad/s $\alpha =0$, respectively, and driving torque(τ) is zero.The link $O_{2}A$ is balanced so that its centre of mass fails at $O_2$. At the instant considered, what is the magnitude of the angular velocity of $O_{4}B$

• A. 1 rad/s
• B. 3 rad/s
• C. 8 rad/s
• D. 64/3 rad/s

Answer 1

The correct option is B 3 rad/s


$\theta =\frac{160-60}{240}=\frac{60}{C{O}_2}$

$\therefore C{O}_2=144$ mm

Now, $\frac{{\omega }_4}{{\omega }_2}=\frac{I_{12}{I}_{24}}{I_{14}{I}_{24}}=\frac{144}{(240+144)}$

$\frac{{\omega }_4}{8}=\frac{144}{384}$

$\therefore {\omega }_4=\frac{144}{384}\times 8=3rad/s$