When a ship travels in a sea, which of the effect is more dangerous
Steering
Pitching
Rolling
All of the above
Correct Answer :
B. Pitching
Related Questions
The dynamic friction is the friction experienced by a body, when the body
Is in motion
Is at rest
Just begins to slide over the surface of the other body
None of the above
The pitching of a ship produces forces on the bearings which act __________ to the motion of the ship.
Vertically and parallel
Vertically and perpendicular
Horizontally and parallel
Horizontally and perpendicular
In a Hartnell governor, the stiffness of the spring is given by (where S1 and S2 = Spring forces exerted on the sleeve at max. and min. radii of rotation, and h = Compression of the spring)
(S₁ + S₂)/h
(S₁ - S₂)/h
(S₁ + S₂)/2h
(S₁ - S₂)/2h
The maximum velocity of a particle moving with simple harmonic motion is
ω
ωr
ω²r
ω/r
Higher 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
Creep in belt drive is due to
Weak material of the belt
Weak material of the pulley
Uneven extensions and contractions of the belt when it passes from tight side to slack side
Expansion of the belt
The condition for correct steering of a Davis steering gear is (where α = Angle of inclination of the links to the vertical)
sinα = b/c
cosα = c/b
tanα = c/2b
cotα = c/2b
In a pantograph, all the pairs are
Turning pairs
Sliding pairs
Spherical pairs
Self-closed pairs
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
Hart mechanism has
Eight links
Six links
Four links
Twelve links
The periodic time of one oscillation for a simple pendulum is
2π. √(g/l)
(1/2π). √(g/l)
2π. √(l/g)
(1/2π). √(l/g)
Which of the following is an open pair?
Ball and socket joint
Journal bearing
Lead screw and nut
Cam and follower
The distance by which the __________ of the D-slide valve overlaps the steam port is called exhaust lap.
Inner edge
Outer edge
Corners
None of these
If the opposite links of a four bar linkage are equal, the links will always form a
Triangle
Rectangle
Parallelogram
Pentagon
The velocity of sliding of meshing gear teeth is (Where ω₁ and ω₂ are angular velocities of meshing gears and y is distance between point of contact and the pitch point)
(ω₁ + ω₂)y
(ω₁/ω₂)y
(ω₁ × ω₂)y
(ω₁ + ω₂)/y
The contact ratio for gears is
Zero
Less than one
Greater than one
Infinity
The periodic time of a compound pendulum is __________ when the distance between the point of suspension and the centre of gravity is equal to the radius of gyration of the body about its centre of gravity.
Zero
Minimum
Maximum
None of these
An imaginary circle which by pure rolling action, gives the same motion as the actual gear, is called
Addendum circle
Dedendum circle
Pitch circle
Clearance circle
Which of the following is a turning pair?
Piston and cylinder of a reciprocating steam engine
Shaft with collars at both ends fitted into a circular hole
Lead screw of a lathe with nut
Ball and a socket joint
The equivalent length of a simple pendulum which gives the same frequency as a compound pendulum is
h/(kG² + h²)
(kG² + h²)/h
h²/(kG² + h²)
(kG² + h²)/h²
The steering of a ship means
Movement of a complete ship up and down in vertical plane about transverse axis
Turning of a complete ship in a curve towards right or left, while it moves forward
Rolling of a complete ship sideways
None of the above
Minimum number of teeth for involute rack and pinion arrangement for pressure angle of 20° is
18
20
30
34
Which of the following is a higher pair?
Belt and pulley
Turning pair
Screw pair
Sliding pair
Davis steering gear consists of
Sliding pairs
Turning pairs
Rolling pairs
Higher pairs
The velocity of the belt for maximum power is (where m = Mass of the belt in kg per metre length)
T/3
(T.g)/3
√(T/3m)
√(3m/T)
In which of the following type of gear train the first gear and the last gear are co-axial.
Simple gear train
Compound gear train
Reverted gear train
None of the above
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)
A watt's governor can work satisfactorily at speeds from
60 to 80 r.p.m.
80 to 100 r.p.m.
100 to 200 r.p.m.
200 to 300 r.p.m.
When the addenda on pinion and wheel is such that the path of approach and path of recess are half of their maximum possible values, then the length of the path of contact is given by (where r = Pitch circle radius of pinion, R = Pitch circle radius of wheel, and φ = Pressure angle)
[(r² + R²) cosφ]/2
[(r² + R²) sinφ]/2
[(r + R) cosφ]/2
[(r + R) sinφ]/2
The size of cam depends upon
Base circle
Pitch circle
Prime circle
Pitch curve