A planar closed kinematic chain is formed with rigid links $$PQ = 2.0 m, QR = 3.0 m, RS = 2.5 m$$ and $$SP = 2.7 m$$ with all revolute joints. The link to be fixed to obtain a double rocker (rocker-rocker) mechanism is

A single degree of freedom system having mass $$1$$ $$kg$$ and stiffness $$10$$ $$kN/m$$ initially at rest is subjected to an impulse force of magnitude $$5$$ $$kN$$ for $${10^{ - 4}}$$ seconds. The amplitude in $$mm$$ of the resulting free vibration is

A flywheel connected to a punching machine has to supply energy of $$400$$ Nm while running at a mean angular speed of $$20$$ rad/s. If the total fluctuation of speed is not to exceed $$ \pm 20\% $$, the mass moment of inertia of the flywheel in kg-m² is

If two nodes are observed at a frequency of $$1800$$ rpm during whirling of a simply supported long slender rotating shaft, the first critical speed of the shaft in rpm is