Theory of Machine
Lower pairs are those which have

Surface contact between the two elements when in motion
Two elements that permit relative motion
Point or line contact between the two elements when in motion
Elements of pairs not held together mechanically

ANSWER DOWNLOAD EXAMIANS APP

Theory of Machine
When a mass of a critically damped single degree of freedom system is deflected from its equilibrium position and released, then it will

Return to equilibrium position without oscillation
Oscillate with decreasing amplitude
Oscillate with constant amplitude
Oscillate with increasing time period

ANSWER DOWNLOAD EXAMIANS APP