Theory of Machine
The critical speed of a shaft with a disc supported in between is equal to the natural frequency of the system in

Longitudinal vibrations
All of these
Transverse vibrations
Torsional vibrations

ANSWER DOWNLOAD EXAMIANS APP

Theory of Machine
The secondary unbalanced force due to inertia of reciprocating parts in a reciprocating engine is given by (where m = Mass of reciprocating parts, ω = Angular speed of crank, r = Radius of crank, θ = Angle of inclination of crank with the line of stroke, and n = Ratio of the length of connecting rod to radius of crank)

m.ω².r sinθ
m.ω².r (cos 2θ/n)
m.ω².r cosθ
m.ω².r (sin 2θ/n)

ANSWER DOWNLOAD EXAMIANS APP