471. If ω/ωn is very high for a body vibrating under steady state vibrations, the phase angle for all values of damping factors, will tend to approach
0°
90°
180°
360°
✅ The correct answer is option C.
Theory of machines MCQs
472. Whitworth quick return motion mechanism consists of three turning pairs and one sliding pair.
Right
Wrong
✅ The correct answer is option A.
473. The gear train usually employed in clocks is a
simple gear train
reverted gear train
sun and planet gear
differential gear
✅ The correct answer is option B.
474. In a screw jack, the effort required to lower the load W is given by
P = W tan(α – φ)
P = W tan(α + φ)
P = W tan(φ – α)
P = W cos(α + φ)
✅ The correct answer is option C.
475. A disturbing mass m1 attached to the rotating shaft may be balanced by a single mass m2 attached in the same plane of rotation as that of m1, such that (where r1 and r2 are the radii of rotation of m1 and m2 respectively)
m1r2 = m2r1
m1r1 = m2r2
m1m2 = r1r2
none of these
✅ The correct answer is option B.
476. For a twin cylinder V-engine, the crank positions for primary reverse cranks and secondary direct cranks are shown in the below figure. The engine is a
30° V-engine
60° V-engine
120° V-engine
150° V-engine
✅ The correct answer is option A.
477. The sliding pairs, turning pairs and screw pairs form lower pairs.
TRUE
FALSE
✅ The correct answer is option A.
478. The frequency of damped vibrations with viscous damping is __________ the frequency of undamped vibrations.
more than
less than
same as
✅ The correct answer is option B.
479. In order to give the primary balance of the reciprocating parts of a multi-cylinder in-line engines,
the algebraic sum of the primary forces must be equal to zero
the algebraic sum of the couples about any point in the plane of the primary forces must be equal to zero
both (a) and (b)
none of these
✅ The correct answer is option C.
480. The frictional torque transmitted in a multi-collared shaft is same as that of a single collared shaft.
Right
Wrong
✅ The correct answer is option A.