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1. |
A tappet valve mechanism in an IC engine comprises a rocker arm ABC that is hinged at B as shown in the figure. The rocker is assumed rigid and it oscillates about the hinge B. The mass moment of inertia of the rocker about B is 10-4 kg.m2. The rocker arm dimensions are a = 3.5 cm and b = 2.5 cm. A pushrod pushes the rocker at location A, when moved vertically by a cam that rotates at N rpm. The pushrod is assumed massless and has a stiffness of 15 N/mm. At the other end C, the rocker pushes a valve against a spring of stiffness 10 N/mm. The valve is assumed massless and rigid.Resonance in the rocker system occurs when the cam shaft runs at a speed of ______ rpm (round off to the nearest integer). |
A. | 790 |
B. | 496 |
C. | 2369 |
D. | 4739 |
Answer» E. | |