Theory of Machine Torsional vibrations are said to occur when the particles of a body moves In a circle about its axis Parallel to its axis Perpendicular to its axis None of these In a circle about its axis Parallel to its axis Perpendicular to its axis None of these ANSWER DOWNLOAD EXAMIANS APP
Theory of Machine In the below figure, PC is the connecting rod and OC is the crank making an angle θ with the line of stroke PO and rotates with uniform angular velocity at ω rad/s. The Klien's acceleration diagram for determining the acceleration of the piston P is shown by quadrilateral CQNO, the acceleration of the piston is _________ when the crank OC and connecting rod PC are at right angles to each other. Zero Any +ve value Infinity Any -ve value Zero Any +ve value Infinity Any -ve value ANSWER DOWNLOAD EXAMIANS APP
Theory of Machine When the two elements of a pair have __________ when in motion, it is said to a lower pair. Body contact Line or point contact None of these Surface contact Body contact Line or point contact None of these Surface contact ANSWER DOWNLOAD EXAMIANS APP
Theory of Machine The static balancing is satisfactory for low speed rotors but with increasing speeds, dynamic balancing becomes necessary. This is because, the Unbalanced forces are not dangerous at higher speeds Unbalanced couples are caused only at higher speeds Effects of unbalances are directly proportional to the speed Effects of unbalances are proportional to the square of the speed Unbalanced forces are not dangerous at higher speeds Unbalanced couples are caused only at higher speeds Effects of unbalances are directly proportional to the speed Effects of unbalances are proportional to the square of the speed 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 (sin 2θ/n) m.ω².r cosθ m.ω².r sinθ m.ω².r (cos 2θ/n) m.ω².r (sin 2θ/n) m.ω².r cosθ m.ω².r sinθ m.ω².r (cos 2θ/n) ANSWER DOWNLOAD EXAMIANS APP
Theory of Machine A disc is a spinning with an angular velocity ω rad/s about the axis of spin. The couple applied to the disc causing precession will be (where I = Mass moment of inertia of the disc, and ωP = Angular velocity of precession of the axis of spin) (1/2).Iω² Iω² I ω ωP (1/2). I ω ωP (1/2).Iω² Iω² I ω ωP (1/2). I ω ωP ANSWER DOWNLOAD EXAMIANS APP
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