A rigid link $$PQ$$ is undergoing plane motion as shown in the figure ($${V_P}$$ and $${V_Q}$$ are non-zero). $${V_{QP}}$$ is the relative velocity of point $$Q$$ with respect to point $$P$$.

Which one of the following is TRUE?

The number of degrees of freedom in a planner mechanism having $$n$$ links and $$j$$ simple hinge joints is

The static deflection of a spring under gravity, when a mass of 1 kg is suspended from it, is 1 mm. Assume the acceleration due to gravity g =10 m/s² . The natural frequency of this spring-mass system (in rad/s) is _____________

A single degree of freedom spring-mass system is subjected to a harmonic force of constant amplitude. For an excitation frequency of $$\sqrt {{{3k} \over m}} ,$$ the ratio of the amplitude of steady state response to the static deflection of the spring is __________