In a reciprocating engine, usually __________ of the reciprocating masses are balanced.
One-half
Two-third
Three-fourth
Whole
Correct Answer :
B. Two-third
Related Questions
A shaft carrying three rotors will have
No node
One node
Two nodes
Three nodes
The maximum efficiency of spiral gears is (where θ = Shaft angle, and φ = Friction angle)
sin (θ + φ) + 1/ cos (θ - φ) + 1
cos (θ - φ) + 1/ sin (θ + φ) + 1
cos (θ + φ) + 1/ cos (θ - φ) + 1
cos (θ - φ) + 1/ cos (θ + φ) + 1
In a coupling rod of a locomotive, each of the four pairs is a ________ pair.
Sliding
Turning
Rolling
Screw
Cam size depends upon
Base circle
Pitch circle
Prime circle
Outer circle
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
When the elements of a pair are kept in contact by the action of external forces, the pair is said to be a
Lower pair
Higher pair
Self-closed pair
Force-closed pair
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
For the brake to be self locking, the force P at C shown in the below figure, should 
Be zero
Act in upward direction
Act in downward direction
None of these
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 sinθ
m.ω².r cosθ
m.ω².r (sin 2θ/n)
m.ω².r (cos 2θ/n)
The velocity of a body moving with simple harmonic motion is __________ at the mean position.
Zero
Minimum
Maximum
None of these
When the particles of a body moves perpendicular to its axis, then the body is said to have
Longitudinal vibration
Transverse vibration
Torsional vibration
None of these
Which of the following is an open pair?
Journal bearing
Ball and Socket joint
Leave screw and nut
None of the above
For the same lift and same angle of ascent, a smaller base circle will give
A small value of pressure angle
A large value of pressure angle
There is no such relation with pressure angle
Something else
In gramophones for adjusting the speed of the turntable, the following type of governor is commonly employed
Hartung governor
Wilson Hartnell governor
Pickering governor
Inertia governor
A point B on a rigid link AB moves with respect to A with angular velocity ω rad/s. The radial component of the acceleration of B with respect to A, is (where vBA = Linear velocity of B with respect to A)
vBA × AB
vBA /AB
v²BA
v²BA /AB
If there are L number of links in a mechanism, then number of possible inversions is equal to
L + 1
L - 1
L
L + 2
In a locomotive, the resultant unbalanced force due to the two cylinders along the line of stroke, is known as
Tractive force
Swaying couple
Hammer blow
None of these
The relation between number of pairs (p) forming a kinematic chain and the number of links (l) is
l = 2p - 2
l = 2p - 3
l = 2p - 4
l = 2p - 5
In a cone pulley, if the sum of radii of the pulleys on the driving and driven shafts is Constant, then
Open belt drive is recommended
Crossed belt drive is recommended
Both open belt drive and crossed belt drive is recommended
The drive is recommended depending upon the torque transmitted
A body of weight W is required to move up the rough inclined plane whose angle of inclination with the horizontal is α. The effort applied parallel to the plane is given by (where μ = tan φ = Coefficient of friction between the plane and the body)
P = W tan α
P = W tan (α + φ)
P = W (sin α + μ cos α)
P = W (cos α + μ sin α)
In a cam drive with uniform velocity follower, the sharp corners of the displacement diagram are rounded off at the beginning and at the end of each stroke. This is done
Because of difficulty in manufacturing cam profile
Because of loose contact of follower with cam surface
In order to have acceleration in beginning and retardation at the end of stroke within the finite limits
Because the uniform velocity motion is a partial parabolic motion
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
Klein's construction can be used when
Crank has a uniform angular velocity
Crank has non-uniform velocity
Crank has uniform angular acceleration
Crank has uniform angular velocity and angular acceleration
In involute gears, the pressure angle is
Dependent on the size of teeth
Dependent on the size of gears
Always constant
Always variable
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 acceleration of a particle moving with simple harmonic motion, at any instant is given by
ωx
ω²x
ω²/x
ω³/x
Whirling speed of the shaft is the speed at which
Shaft tends to vibrate in longitudinal direction
Torsional vibrations occur
Shaft tends to vibrate vigorously in transverse direction
Combination of transverse and longitudinal vibration occurs
In its simplest form, a cam mechanism consists of following number of links
1
2
3
4
A rigid body, under the action of external forces, can be replaced by two masses placed at a fixed distance apart. The two masses form an equivalent dynamical system, if
The sum of the two masses is equal to the total mass of body
The centre of gravity of the two masses coincides with that of the body
The sum of mass moment of inertia of the masses about their centre of gravity is equal to the mass moment of inertia of the body
All of the above
Which of the following statement is correct?
The periodic time of a particle moving with simple harmonic motion is the time taken by a particle for one complete oscillation.
The periodic time of a particle moving with simple harmonic motion is directly proportional to its angular velocity.
The velocity of a particle moving with simple harmonic motion is zero at the mean position.
The acceleration of the particle moving with simple harmonic motion is maximum at the mean position.