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)
Correct Answer :
C. √(T/3m)
Related Questions
The sensitiveness of the governor __________ as the speed range decreases.
Remains unaffected
Decreases
Increases
None of these
In a gear having involute teeth, the normal to the involute is a tangent to the
Pitch circle
Base circle
Addendum circle
Dedendum circle
The component of the acceleration, perpendicular to the velocity of the particle, at the given instant is called
Radial component
Tangential component
Coriolis component
None of these
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°
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
Ball and a Socket forms a
Turning pair
Rolling pair
Screw pair
Spherical pair
If the number of links in a mechanism is equal to l, then the numbers of possible inversions are equal to
l - 2
l - 1
l
l + 1
The pressure angle of a cam depends upon
Offset between centre lines of cam and follower
Lift of follower
Angle of ascent
All of the above
The frequency of oscillation at compared to earth will be
6 times more
6 times less
2.44 times more
2.44 times less
The ratio of height of Porter governor (when length of arms and links are equal) to the height of Watt's governor is (where m = Mass of the ball, and M = Mass on the sleeve)
m/(m + M)
M/(m + M)
(m + M)/m
(m + M)/M
The two parallel and coplanar shafts are connected by gears having teeth parallel to the axis of the shaft. This arrangement is known as
Spur gearing
Helical gearing
Bevel gearing
Spiral gearing
The dedendum circle diameter is equal to (where, φ = Pressure angle)
Pitch circle dia. × cosφ
Addendum circle dia. × cosφ
Clearance circle dia. × cosφ
Pitch circle dia. × sinφ
The direction of linear velocity of any point on a link with respect to another point on the same link is
Parallel to the link joining the points
Perpendicular to the link joining the points
At 45° to the link joining the points
None of the above
The power of a Porter governor is equal to
[c²/(1 + 2c)] (m + M) g.h
[2c²/(1 + 2c)] (m + M) g.h
[3c²/(1 + 2c)] (m + M) g.h
[4c²/(1 + 2c)] (m + M) g.h
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
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 clockwise 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
Cam size depends upon
Base circle
Pitch circle
Prime circle
Outer circle
The Kutzbach criterion for determining the number of degrees of freedom (n) is (where l = number of links, j = number of joints and h = number of higher pairs)
n = 3(l - 1) - 2j - h
n = 2(l - 1) -2j - h
n = 3(l - 1) - 3j - h
n = 2(l - 1) - 3j - h
A point B on a rigid link AB moves with respect to A with angular velocity ω rad/s. The total acceleration of B with respect to A will be equal to
Vector sum of radial component and coriolis component
Vector sum of tangential component and coriolis component
Vector sum of radial component and tangential component
Vector difference of radial component and tangential component
Efficiency of a screw jack is given by
tan (α + φ)/tanα
tanα/tan (α +φ)
tan (α - φ)/tanα
tanα/tan (α - φ)
When a body is subjected to transverse vibrations, the stress induced in a body will be
Shear stress
Bending stress
Tensile stress
Compressive stress
The frequency of damped vibrations with viscous damping is ________ the frequency of undamped vibrations.
More than
Less than
Same as
None of these
When two pulleys are connected by means of a cross belt drive, then both the pulleys will rotate in __________ directions.
Same
Opposite
Perpendicular
None of these
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 a ship travels in a sea, which of the effect is more dangerous
Steering
Pitching
Rolling
All of the above
In a coupling rod of a locomotive, each of the four pairs is a ________ pair.
Sliding
Turning
Rolling
Screw
The instantaneous centre of a rigid thin disc rolling on a plane rigid surface is located at
The centre of the disc
The point of contact
An infinite distance on the plane surface
The point on the circumference situated vertically opposite to the contact point
Two pulleys of radii r₁ and r₂ and at distance x apart are connected by means of a cross belt drive. The length of the belt is
π (r₁ + r₂) + [(r₁ + r₂)²/x] + 2x
π (r₁ + r₂) + [(r₁ - r₂)²/x] + 2x
π (r₁ - r₂) + [(r₁ - r₂)²/x] + 2x
π (r₁ - r₂) + [(r₁ + r₂)²/x] + 2x
If the damping factor for a vibrating system is unity, then the system will be
Over damped
Under damped
Critically damped
Without vibrations
If the pressure angle is __________, a reciprocating follower will jam in its bearings.
Small
Too small
Large
Too large