The displacement of the D-slide valve is __________ the steam lap by a distance known as lead of the valve.
Greater than
Less than
Equal to
None of these
Correct Answer :
A. Greater than
Related Questions
When the two elements of a pair have __________ when in motion, it is said to a lower pair.
Line or point contact
Surface contact
Body contact
None of these
The type of pair formed by two elements which are so connected that one is constrained to turn or revolve about a fixed axis of another element is known as
Turning pair
Rolling pair
Sliding pair
Spherical pair
Tangential acceleration direction is
Along the angular velocity
Opposite to angular velocity
May be any one of these
Perpendicular to angular velocity
The frictional torque transmitted in a flat collar bearing, considering uniform wear, is (where r₁ and r₂ = External and internal radii of collar respectively)
(1/2) μ W (r₁ + r₂)
(2/3) μ W (r₁ + r₂)
(1/2) μ W [(r₁³ - r₂³)/(r₁² - r₂²)]
(2/3) μ W [(r₁³ - r₂³)/(r₁² - r₂²)]
The tractive force in a locomotive with two cylinders is given by (where c = Fraction of reciprocating parts per cylinder, m = Mass of reciprocating parts, ω = Angular speed of crank, r = Radius of crank, and θ = Angle of inclination of crank to the line of stroke)
m.ω².r cosθ
c.m.ω².r sinθ
(1 - c).m.ω².r (cosθ - sinθ)
m.ω².r (cosθ - sinθ)
In a circular arc cam with roller follower, the acceleration in any position of the lift will depend only upon
Total lift, total angle of lift, minimum radius of cam and cam speed
Radius of circular arc, cam speed, location of centre of circular arc and roller diameter
Mass of cam follower linkage, spring stiffness and cam speed
Total lift, centre of gravity of the cam and cam speed
The partial balancing means
Balancing partially revolving masses
Balancing partially reciprocating masses
Best balancing of engines
All of these
The two links OA and OB are connected by a pin joint at O. If the link OA turns with angular velocity ω₁ rad/s in the clockwise direction and the link OB turns with angular velocity ω₂ rad/s in the anticlockwise direction, then the rubbing velocity at the pin joint O is (where r = Radius of the pin at O)
ω₁.ω₂.r
(ω₁ - ω₂) r
(ω₁ + ω₂) r
(ω₁ - ω₂) 2r
If two moving elements have surface contact in motion, such pair is known as
Sliding pair
Rolling pair
Surface pair
Higher pair
The ratio of the number of teeth to the pitch circle diameter in millimetres, is called
Circular pitch
Diametral pitch
Module
None of these
The rotating shafts tend to vibrate violently at whirling speeds because
The system is unbalanced
Bearing centre line coincides with the axis
The shafts are rotating at very high speeds
Resonance is caused due to the heavy mass of the rotor
A spring controlled governor is found unstable. It can be made stable by
Increasing the spring stiffness
Decreasing the spring stiffness
Increasing the ball mass
Decreasing the ball mass
The essential condition of placing the two masses, so that the system becomes dynamically equivalent, is (where l₁ and l₂ = Distance of two masses from the centre of gravity of the body, and kG = Radius of gyration of the body)
l₁ = kG
l₂ = kG
l₁l₂ = kG
l₁l₂ = kG²
The static balancing is satisfactory for low speed rotors but with increasing speeds, dynamic balancing becomes necessary. This is because, the
Unbalanced couples are caused only at higher speeds
Unbalanced forces are not dangerous at higher speeds
Effects of unbalances are proportional to the square of the speed
Effects of unbalances are directly proportional to the speed
Which of the following statement is correct as regard to the difference between a machine and a structure?
The parts of a machine move relative to one another, whereas the members of a structure do not move relative to one another
The links of a machine may transmit both power and motion, whereas the members of a structure transmit forces only
A machine transforms the available energy into some useful work, whereas in a structure no energy is transformed into useful work
All of the above
Which of the following is an example of a higher pair?
Toothed gearing
Belt and rope drive
Ball and roller bearing
All of these
For an involute gear, the ratio of base circle radius and pitch circle radius is equal to
sinφ
cosφ
secφ
cosecφ
Lower 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
A single degree of freedom system is given by, m × (d²x/dt²) + c × (dx/dt) + sx = F.cosω.t with usual notations. It represents
Free vibration with damping
Free vibration without damping
Forced vibration with damping
Forced vibration without damping
For two governors A and B, the lift of sleeve of governor A is more than that of governor B, for a given fractional change in speed. It indicates that
Governor A is more sensitive than governor B
Governor B is more sensitive than governor A
Both governors A and B are equally sensitive
None of the above
Ackermann steering gear consists of
Sliding pairs
Turning pairs
Rolling pairs
Higher pairs
Klein's construction gives a graphic construction for
Slider-crank mechanism
Velocity polygon
Acceleration polygon
Four bar chain mechanism
In locomotives, the ratio of the connecting rod length to me crank radius is kept very large in order to
Minimise the effect of primary forces
Minimise the effect of secondary forces
Have perfect balancing
To start the locomotive quickly
The frequency of oscillation of a compound pendulum is
2π. √[gh/(kG² + h²)]
2π. √[(kG² + h²)/gh]
(1/2π). √[gh/(kG² + h²)]
(1/2π). √[(kG² + h²)/gh]
The natural frequency of free longitudinal vibrations is equal to (where m = Mass of the body, s = Stiffness of the body, and δ = Static deflection of the body)
1/2π × √(s/m)
1/2π × √(g/δ)
0.4985/√δ
Any one of these
When the nature of contact between the elements of a pair is such that it can only slide relative to the other, the pair is known as a
Screw pair
Spherical pair
Turning pair
Sliding pair
In a four bar chain or quadric cycle chain
Each of the four pairs is a turning pair
One is a turning pair and three are sliding pairs
Two are turning pairs and two are sliding pairs
Three are turning pairs and one is a sliding pair
Which of the following statement is correct?
For constant velocity ratio transmission between two gears, the common normal at the point of contact must always pass through a fixed point on the line joining the centres of rotation of gears.
For involute gears, the pressure angle changes with the change in centre distance between gears.
The epicyclic gear trains involve rotation of atleast one gear axis about some other gear axis.
All of the above
The primary unbalanced force is maximum _________ in one revolution of the crank.
Twice
Four times
Eight times
Sixteen times
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