In a footstep bearing, if the radius of the shaft is doubled, then the torque required to overcome the viscous resistance will be
Double
Four times
Eight times
Sixteen times
Correct Answer :
D. Sixteen times
Related Questions
According to Bernoulli's equation
Z + p/w + v²/2g = constant
Z + p/w - v²/2g = constant
Z - p/w + v²/2g = constant
Z - p/w - v²/2g = constant
The pressure in Pascals at a depth of 1 m below the free surface of a body of water will be equal to
1 Pa
91 Pa
981 Pa
9810 Pa
One cubic metre of water weighs
100 litres
250 litres
500 litres
1000 litres
The maximum discharge over a broad crested weir is
0.384 Cd × L × H1/2
0.384 Cd × L × H3/2
1.71 Cd × L × H1/2
1.71 Cd × L × H3/2
The discharge through a channel of rectangular section will be maximum, if
Its depth is twice the breadth
Its breadth is twice the depth
Its depth is thrice the breadth
Its breadth is thrice the depth
The total pressure on the top of a closed cylindrical vessel completely filled up with a liquid is
Directly proportional to (radius)2
Inversely proportional to (radius)2
Directly proportional to (radius)4
Inversely proportional to (radius)4
Viscous force is the __________ of shear stress due to viscosity and cross-section area of flow.
Sum
Different
Product
Ratio
The specific weight of water is 1000 kg/m3
At normal pressure of 760 mm
At 4°C temperature
At mean sea level
All the above
The discharge over a triangular notch is
Inversely proportional to H3/2
Directly proportional to H3/2
Inversely proportional to H5/2
Directly proportional to H5/2
The flow which neglects changes in a transverse direction is known as
One dimensional flow
Uniform flow
Steady flow
Turbulent flow
A manometer is used to measure
Low pressure
Moderate pressure
High pressure
Atmospheric pressure
Differential manometer is used to measure
Pressure in pipes, channels etc.
Atmospheric pressure
Very low pressure
Difference of pressure between two points
The most economical section of a trapezoidal channel is one which has hydraulic mean depth equal to
1/2 × depth
1/2 × breadth
1/2 × sloping side
1/4 × (depth + breadth)
Bulk modulus of a fluid is the ratio of
Shear stress to shear strain
Increase in volume to the viscosity of fluid
Increase in pressure to the volumetric strain
Critical velocity to the viscosity of fluid
Falling drops of water become spheres due to the property of
Adhesion
Cohesion
Surface tension
Viscosity
The pressure measured with the help of a Piezometer tube is in
N/mm2
N/m2
Head of liquid
All of these
The dynamic viscosity of the liquid __________ with rise in temperature.
Remain unaffected
Increases
Decreases
None of these
A streamline is defined as the line
Parallel to central axis flow
Parallel to outer surface of pipe
Of equal velocity in a flow
Along which the pressure drop is uniform
The error in discharge (dQ/Q) to the error in measurement of head (dH/H) over a triangular notch is given by
dQ/Q = 3/2 × (dH/H)
dQ/Q = 2 × (dH/H)
dQ/Q = 5/2 × (dH/H)
dQ/Q = 3 × (dH/H)
The discharge through a convergent mouthpiece is __________ the discharge through an internal mouthpiece of the same diameter and head of water.
Equal to
One-half
Three fourth
Double
The pressure in the air space above an oil (sp. gr. 0.8) surface in a tank is 0.1 kg/cm. The pressure at 2.5 m below the oil surface will be
2 metres of water column
3 metres of water column
3.5 metres of water column
4 m of water column
A vertical wall is subjected to a pressure due to one kind of liquid, on one of its sides. Which of the following statement is correct?
The pressure on the wall at the liquid level is minimum
The pressure on the bottom of the wall is maximum
The pressure on the wall at the liquid level is zero, and on the bottom of the wall is maximum
The pressure on the bottom of the wall is zer
Viscosity of water in comparison to mercury is
Higher
Lower
Same
Higher/lower depending on temperature
Two pipe systems can be said to be equivalent, when the following quantities are same
Friction loss and flow
Length and diameter
Flow and length
Friction factor and diameter
Choose the wrong statement
Viscosity of a fluid is that property which determines the amount of its resistance to a shearing force
Viscosity is due primarily to interaction between fluid molecules
Viscosity of liquids decreases with increase in temperature
Viscosity of liquids is appreciably affected by change in pressure
When a cylindrical vessel containing liquid is revolved about its vertical axis at a constant angular velocity, the pressure
Varies as the square of the radial distance
Increases linearly as its radial distance
Increases as the square of the radial distance
Decreases as the square of the radial distance
Cavitation will begin when
The pressure at any location reaches an absolute pressure equal to the saturated vapour pressure of the liquid
Pressure becomes more than critical pressure
Flow is increased
Pressure is increased
The resultant of all normal pressures acts
At C.G. of body
At center of pressure
Vertically upwards
At metacentre
The pressure intensity in kN/m2 (or kPa) at any point in a liquid is (where w = Specific weight of liquid, and h = Depth of liquid from the surface)
w
wh
w/h
h/w
The critical depth for a channel is given by (where q = Unit discharge (discharge per unit width) through the channel)
(q/g)1/2
(q²/g)1/3
(q³/g)1/4
(q⁴/g)1/5