When the crank is at the inner dead centre, in a reciprocating steam engine, then the acceleration of the piston will be
ω²r. (n + 1)/n
ω²r. (n - 1)/n
ω²r. n/(n + 1)
ω²r. n/(n - 1)
Correct Answer :
A. ω²r. (n + 1)/n
Related Questions
Which of the following property of the instantaneous centre is correct?
A rigid link rotates instantaneously relative to another link at the instantaneous centre for the configuration of the mechanism considered.
The two rigid links have no linear velocity relative to each other at the instantaneous centre.
The velocity of the instantaneous centre relative to any third rigid link is same whether the instantaneous centre is regarded as a point on the first rigid link or on the second rigid link.
All of the above
Which gear train is used for higher velocity ratios in a small space?
Simple gear train
Compound gear train
Reverted gear train
Epicyclic gear train
For an isochronous Hartnell governor (where r₁ and r₂ = Maximum and minimum radius of rotation of balls respectively, S₁ and S₂ = Maximum and minimum force exerted on the sleeve respectively, and M = Mass on the sleeve)
(m.g + S₁)/(m.g + S₂) = r₁/r₂
(m.g - S₁)/(m.g - S₂) = r₂/r₁
S₁/S₂ = r₁/r₂
S₂/S₁ = r₁/r₂
Power of a governor is the
Mean force exerted at the sleeve for a given percentage change of speed
Workdone at the sleeve for maximum equilibrium speed
Mean force exerted at the sleeve for maximum equilibrium speed
None of the above
The Ackerman steering gear mechanism is preferred to the Davis steering gear mechanism, because
Whole of the mechanism in the Ackerman steering gear is on the back of the front wheels
The Ackerman steering gear consists of turning pairs
The Ackerman steering gear is most economical
Both (A) and (B)
A system of masses rotating in different parallel planes is in dynamic balance if the
Resultant force is equal to zero
Resultant couple is equal to zero
Resultant force and resultant couple are both equal to zero
Resultant force is numerically equal to the resultant couple, but neither of them need necessarily be zero
The centre of percussion is below the centre of gravity of the body and is at a distance equal to
h/kG
h²/kG
kG²/h
h × kG
The example of successfully constrained motion is a
Motion of an I.C. engine valve
Motion of the shaft between a footstep bearing
Piston reciprocating inside an engine cylinder
All of the above
The minimum force required to slide a body of weight W on a rough horizontal plane is
W sinθ
W cosθ
W tanθ
W cosecθ
The unbalanced force due to revolving masses
Varies in magnitude but constant in direction
Varies in direction but constant in magnitude
Varies in magnitude and direction both
Constant in magnitude and direction both
A simple spring-mass vibrating system has a natural frequency of fn. If the spring stiffness is halved and the mass is doubled, then the natural frequency will become
fn/2
2 fn
4 fn
8 fn
In considering friction of a V-thread, the virtual coefficient of friction (μ₁) is given by
μ₁ = μ sinβ
μ₁ = μ cosβ
μ₁ = μ/sinβ
μ₁ = μ/cosβ
Rectilinear motion of piston is converted into rotary by
Cross head
Slider crank
Connecting rod
Gudgeon pin
The frictional torque transmitted in a flat pivot bearing, considering uniform wear, is (where μ = Coefficient of friction, W = Load over the bearing, and R = Radius of bearing surface)
(1/2) μ W R
(2/3) μ W R
(3/4) μ W R
μ W R
In a Hartnell governor, if a spring of greater stiffness is used, then the governor will be
Less sensitive
More sensitive
Unaffected of sensitivity
Isochronous
A slider moves at a velocity v on a link revolving at ω rad/s. The coriolis component of acceleration is
ωv
2ωv
ω²v
2ωv²
Which one of the following is an exact straight line mechanism using lower pairs?
Watts mechanism
Grasshopper mechanism
Roberts mechanism
Peaucelliers mechanism
The swaying couple is maximum or minimum when the angle of inclination of the crank to the line of stroke (θ) is equal to
90° and 180°
45° and 225°
180° and 270°
270° and 360°
When the load on the engine increases, it becomes necessary to increase the supply of working fluid and when the load decreases, less working fluid is required. The supply of the working fluid to the engine is controlled by a
D-slide valve
Governor
Meyer's expansion valve
Flywheel
Kinematic pairs are those which have
Point or line contact between the two elements when in motion
Surface contact between the two elements when in motion
Elements of pairs not held together mechanically
Two elements that permit relative motion
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 increasing time period
Oscillate with decreasing amplitude
Oscillate with constant amplitude
The approximate straight line mechanism is a
Four bar linkage
6 bar linkage
8 bar linkage
3 bar linkage
Sense of tangential acceleration of a link
Is same as that of velocity
Is opposite to that of velocity
Could be either same or opposite to velocity
Is perpendicular to that of velocity
The motion between a pair which takes place in __________ is known as incompletely constrained motion.
One direction only
Two directions only
More than one direction
None of these
In a vibrating system, if the actual damping coefficient is 40 N/m/s and critical damping coefficient is 420 N/m/s, then logarithmic decrement is equal to
0.2
0.4
0.6
0.8
A cam with a roller follower would constitute following type of pair
Lower pair
Higher pair
Open pair
Close pair
A rotor which is balanced statically but not dynamically is supported on two bearings L apart and at high speed of the rotor, reaction on the left bearing is R. The right side of the bearing is shifted to a new position 2L apart from the left bearing. At the same rotor speed, dynamic reaction on the left bearing in the new arrangement will
Remain same as before
Become equal to 2R
Become equal to R/2
Become equal to R/4
A rotor supported at A and B carries two masses as shown in the below figure. The rotor is 
Dynamically balanced
Statically balanced
Statically and dynamically balanced
Not balanced
Coriolis component is encountered in
Quick return mechanism of shaper
Four bar chain mechanism
Slider crank mechanism
Both (A) and (C) above
The equation of motion for a vibrating system with viscous damping is (d²x/dt²) + (c/m). (dx/dt) + (s/m). x = 0 If the roots of this equation are real, then the system will be
Over-damped
Under damped
Critically damped
Without vibrations