The velocity ratio of a differential pulley block with D and d as the diameters of larger and smaller pulley, is
D/(D - d)
D/(D + d)
2D/(D - d)
2D/(D + d)
Correct Answer :
C. 2D/(D - d)
Related Questions
Which of the following is not the unit of energy?
kg m
kcal
Watt
Watt hours
In the lever of third order, load W, effort P and fulcrum F are oriented as follows
W between P and F
F between W and P
P between W and F
W, P and F all on one side
The velocity ratio in case of an inclined plane inclined at angle θ to the horizontal and weight being pulled up the inclined plane by vertical effort is
sinθ
cosθ
tanθ
cosecθ
A smooth cylinder lying on its convex surface remains in __________ equilibrium.
Stable
Unstable
Neutral
None of these
The minimum force required to slide a body of weight W on a rough horizontal plane is
W sinθ
W cosθ
W tanθ
None of these
If the number of pulleys in a system is equal to its velocity ratio, then it is a __________ system of pulleys
First
Second
Third
None of these
The centre of gravity of a quadrant of a circle lies along its central radius (r) at a distance of
0.5r
0.6 r
0.7 r
0.8 r
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Ratio of limiting friction and normal reaction
The friction force acting when the body is just about to move
The friction force acting when the body is in motion
If a suspended body is struck at the centre of percussion, then the pressure on die axis passing through the point of suspension will be
Maximum
Minimum
Zero
Infinity
The centre of percussion of a solid cylinder of radius r resting on a horizontal plane will be
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r/A
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The periodic time of a particle with simple harmonic motion is __________ proportional to the angular velocity.
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Inversely
Square root
None of these
Efficiency of a screw jack is given by (where α = Helix angle, and φ = Angle of friction.)
tan(α + φ)/tanα
tanα/tan (α + φ)
tan(α - φ)/tanα
None of these
The centre of gravity of a right circular solid cone is at a distance of __________ from its base, measured along the vertical axis. (where h = Height of a right circular solid cone.)
h/2
h/3
h/4
h/6
Pick up wrong statement about friction force for dry surfaces. Friction force is
Proportional to normal load between the surfaces
Dependent on the materials of contact surface
Proportional to velocity of sliding
Independent of the area of contact surfaces
The linear acceleration (a) of a body rotating along a circular path of radius (r) with an angular acceleration of α rad/s2, is
a = α/ r
a = α.r
a = r / α
None of these
Two coplanar couples having equal and opposite moments
Balance each other
Produce a couple and an unbalanced force
Are equivalent
Cannot balance each other
A pair of smith's tongs is an example of the lever of
Zeroth order
First order
Second order
Third order
If rain is falling in the opposite direction of the movement of a pedestrian, he has to hold his umbrella
More inclined when moving
Less inclined when moving
More inclined when standing
Less inclined when standing
The efficiency of a screw jack is maximum, when (where α = Helix angle, and φ = Angle of friction.)
α = 45° + φ/2
α = 45° - φ/2
α = 90° + φ
α = 90° - φ
The angle between two forces when the resultant is maximum and minimum respectively are:
0° and 180°
180° and 0°
90° and 180°
90° and 0°
The centre of gravity of an isosceles triangle with base (p) and sides (q) from its base is
[√(4p² - q²)]/6
(4p² - q²)/6
(p² - q²)/4
(p² + q²)/4
The C.G. of a solid hemisphere lies on the central radius 3r
At distance from the plane base 3r
At distance from the plane base 3r
At distance from the plane base 3r
At distance from the plane base
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Algebraic sum of the horizontal components of all the forces should be zero
Algebraic sum of the vertical components of all the forces should be zero
Algebraic sum of moments of all the forces about any point should be zero
All of the above
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h/2
J/3
h/6
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1/2
2/3
3/2
2/4
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h [(2a + b)/(a + b)]
(h/2) [(2a + b)/(a + b)]
(h/3) [(2a + b)/(a + b)]
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Gravitational pull exerted by the earth
Forces experienced by body in atmosphere
Force of attraction experienced by particles
Gravitational force of attraction towards the centre of the earth
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Less than
Greater than
Equal to
None of these
The moment of inertia of a thin rod of mass m and length l, about an axis through its centre of gravity and perpendicular to its length is
ml2/4
ml2/ 6
ml2/8
ml2/12
Which of the following is a vector quantity?
Energy
Mass
Momentum
Angle