Question

In a slider crank mechanism, the crank rotates with uniform angular velocity. The angular acceleration of the connecting rod will be zero when the

• A. crank is aligned with the line of stroke
• B. crank is perpendicular to the line of stroke
• C. crank is perpendicular to the connecting rod
• D. both a and b

Answer 1

The correct option is A crank is aligned with the line of stroke

The angular acceleration of connecting and is given by

${\alpha }_c=-{\omega }^2\sin \theta \left(\frac{n^2-1}{(n^2-{\sin }^2\theta {)}^{3/2}}\right)$

${\alpha }_c=0$ when $\sin \theta =0$ i.e, at $\theta =0^{\circ }or{180}^{\circ }$

Thus when crank is aligned with line of stroke the angular acceleration of connecting rod is zero.