Moment of inertia of a hollow circular section, as shown in the below figure about X-axis, is 
π/16 (D² - d²)
π/16 (D³ - d³)
π/32 (D⁴ - d⁴)
π/64 (D⁴ - d⁴)
Correct Answer :
D. π/64 (D⁴ - d⁴)
Related Questions
A body of mass m moving with a constant velocity v strikes another body of same mass moving with same velocity but in opposite direction. The common velocity of both the bodies after collision is
v
2v
4v
8v
A sample of metal weighs 219 gms in air, 180 gms in water, 120 gms in an unknown fluid. Then which is correct statement about density of metal
Density of metal can't be determined
Metal is twice as dense as water
Metal will float in water
Metal is twice as dense as unknown fluid
If u1 and u2 are the velocities of two moving bodies in the same direction before impact and v1 and v2 are their velocities after impact, then coefficient of restitution is given by
(v1 - v2)/(u1 - u2)
(v₂ - v₁)/(u1 - u2)
(u1 - u2)/(v1 - v2)
(u₂ + u₁)/(v₂ + v₁)
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 the 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.
Which of the following do not have identical dimensions?
Momentum and impulse
Torque and energy
Torque and work
Moment of a force and angular momentum.
The forces which do not meet at one point and their lines of action do not lie on the same plane are known as
Coplanar concurrent forces
Coplanar non-concurrent forces
Non-coplanar concurrent forces
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 frequency of oscillation of a compound pendulum is (where kG = Radius of gyration about the centroidal axis, and h = Distance between the point of suspension and C.G. of the body.)
2π. √(gh/kG² + h²)
2π. √(kG² + h²/gh)
1/2π. √(gh/kG² + h²)
1/2π. √(kG² + h²/gh)
A circular hole of 50 mm diameter is cut out from a circular disc of 100 mm diameter as shown in the below figure. The centre of gravity of the section will lie 
In the shaded area
In the hole
At O
None of these
Coplanar non-concurrent forces are those forces which __________ at one point, but their lines of action lie on the same plane.
Meet
Do not meet
Either A or B
None of these
The rate of change of momentum is directly proportional to the impressed force, and takes place in the same direction in which the force acts. This statement is known as
Newton's first law of motion
Newton's second law of motion
Newton's third law of motion
None of these
A block of mass 20 kg lying on a rough horizontal plane is connected by a light string passing over a smooth pulley to another mass 5 kg, which can move freely in the Vertical direction, as shown in the below figure. The tension in the string will __________ with the increase in coefficient of friction. 
Increase
Decrease
Not be effected
None of these
The angle which an inclined plane makes with the horizontal when a body placed on it is about to move down is known as angle of
Friction
Limiting friction
Repose
Kinematic friction
A force acting on a body may
Change its motion
Balance the other forces acting on it
Retard its motion
All of the above
Moment of inertia of a hollow circular section, as shown in the below figure about an axis perpendicular to the section, is __________ than that about X-X axis. 
Two times
Same
Half
None of these
The horizontal range of a projectile (R) is given by
R = u² cos2α/g
R = u² sin2α/g
R = u² cosα/g
R = u² sinα/g
The algebraic sum of moments of the forces forming couple about any point in their plane is
Equal to the moment of the couple
Constant
Both of above are correct
Both of above are wrong
The velocity of a particle moving with simple harmonic motion is __________ at the mean position.
Zero
Minimum
Maximum
None of these
The force induced in the string BC due to the load W as shown in the below figure is 
W sinθ
W cosθ
W tanθ
W cotθ
The Cartesian equation of trajectory is (where u = Velocity of projection, α = Angle of projection, and x, y = Co-ordinates of any point on the trajectory after t seconds.)
y = (gx²/2u² cos²α) + x. tanα
y = (gx²/2u² cos²α) - x. tanα
y = x. tanα - (gx²/2u² cos²α)
y = x. tanα + (gx²/2u² cos²α)
Moment of inertia of a hollow rectangular section as shown in the below figure about X-X axis, is 
(BD³/12) - (bd³/12)
(DB³/12) - (db³/12)
(BD³/36) - (bd³/36)
(DB³/36) - (db³/36)
Moment of inertia of a rectangular section having width (b) and depth (d) about an axis passing through its C.G. and parallel to the depth (d), is
db3/12
bd³/12
db³/36
bd³/36
If the body falls freely under gravity, then the gravitational acceleration is taken as
+8.9 m/s2
-8.9 m/s2
+9.8 m/s2
-9.8 m/s2
The acceleration of a particle moving with simple harmonic motion, at any instant is given by
ω.y
ω2.y
ω2/y
ω3.y
The maximum velocity of a particle moving with simple harmonic motion is
ω
ωr
ω2r
ω/r
The ratio of static friction to dynamic friction is always
Equal to one
Less than one
Greater than one
None of these
The acceleration of a particle moving with simple harmonic motion is __________ at the mean position.
Zero
Minimum
Maximum
None of these
The length of a second's pendulum is
94.9 cm
99.4 cm
100 cm
101 cm
The unit of angular velocity is
m/min
rad/s
Revolutions/min
Both (B) and (C)
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