When a body of mass moment of inertia I (about a given axis) is rotated about that axis with an angular velocity to, then the kinetic energy of rotation is
Iω
Iω2
0.5 Iω
0.5 Iω2
Correct Answer :
D. 0.5 Iω2
Related Questions
The amplitude is always __________ radius of the circle.
Equal to
Less than
Greater than
None of these
A heavy ladder resting on floor and against a vertical wall may not be in equilibrium, if
The floor is smooth, the wall is rough
The floor is rough, the wall is smooth
The floor and wall both are smooth surfaces
The floor and wall both are rough surfaces
The moment of inertia of a solid sphere of mass m and radius r is
2mr2/3
2mr2/5
mr2
mr2/2
The product of either force of couple with the arm of the couple is called
Resultant couple
Moment of the forces
Resulting couple
Moment of the couple
The moment of inertia of a square of side (a) about an axis through its centre of gravity is
a4/4
a4/8
a4/12
a4/36
The maximum acceleration of a particle moving with simple harmonic motion is
ω
ωr
ω2r
ω/r
Work done is said to be zero, when
Some force acts on a body, but displacement is zero
No force acts on a body but some displacement takes place
Either (A) or (B)
None of the above
A flywheel on a motor goes from rest to 1000 rpm in 6 sec. The number of revolutions made is nearly equal to
25
50
100
250
A particle inside a hollow sphere of radius r, having coefficient of friction μ can rest up to height of
r/2
r/A
r/3
0.134 r
In actual machines, mechanical advantage is __________ velocity ratio.
Equal to
Less than
Greater than
None of these
Varingon's theorem of moments states that if a number of coplanar forces acting on a particle are in equilibrium, then
Their algebraic sum is zero
Their lines of action are at equal distances
The algebraic sum of their moments about any point in their plane is zero
The algebraic sum of their moments about any point is equal to the moment of their resultant force about the same point.
A lead ball with a certain velocity is made to strike a wall, it falls down, but rubber ball of same mass and with same velocity strikes the same wall, it rebounds. Select the correct reason from the following:
Both the balls undergo an equal change in momentum
The change in momentum suffered by rubber ball is more than the lead ball
The change in momentum suffered by rubber ball is less than the lead ball
None of the above
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
A ladder is resting on a rough ground and leaning against a smooth vertical wall. The force of friction will act
Downward at its upper end
Upward at its upper end
Zero at its upper end
Perpendicular to the wall at its upper end
Which of the following is the locus of a point that moves in such a manner that its distance from a fixed point is equal to its distance from a fixed line multiplied by a constant greater than one
Ellipse
Hyperbola
Parabola
Circle
If the resultant of two equal forces has the same magnitude as either of the forces, then the angle between the two forces is
30°
60°
90°
120°
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
In order to completely specify angular displacement by a vector, it must fix
Direction of the axis of rotation
Magnitude of angular displacement
Sense of angular displacement
All of these
A semicircular disc rests on a horizontal surface with its top flat surface horizontal and circular portion touching down. The coefficient of friction between semi circular disc and horizontal surface is μ. This disc is to be pulled by a horizontal force applied at one edge and it always remains horizontal. When the disc is about to start moving, its top horizontal force will
Remain horizontal
Slant up towards direction of pull
Slant down towards direction of pull
None of the above
Two bodies of masses m1 and m2 are hung from the ends of a rope, passing over a frictionless pulley as shown in the figure below. The acceleration of the string will be 
g (m1 - m2)/(m1 + m2)
2g (m1 - m2)/(m1 + m2)
g (m1 + m2)/(m1 - m2)
2g (m1 + m2)/(m1 - m2)
In ideal machines, mechanical advantage is __________ velocity ratio.
Equal to
Less than
Greater than
None of these
If a rigid body is in equilibrium under the action of three forces, then
These forces are equal
The lines of action of these forces meet in a point
The lines of action of these forces are parallel
Both (B) and (C) above
The impact between two lead spheres is approximately equal to an __________ impact.
Elastic
Inelastic
Solid
None of these
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
A spherical body is symmetrical about its perpendicular axis. According to Routh's rule, the moment of inertia of a body about an axis passing through its centre of gravity is (where, M = Mass of the body, and S = Sum of the squares of the two semi-axes.)
MS/3
MS/4
MS/5
None of these
The term 'Centroid' is
The same as centre of gravity
The point of suspension
The point of application of the resultant of all the forces tending to cause a body to rotate about a certain axis
None of the above
The maximum mechanical advantage of a lifting machine is
1 + m
1 - m
1 / m
m
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 units of moment of inertia of mass are
kg-m²
m²/kg.
kg/m²
kg/m
A rubber ball is dropped from a height of 2 m. If there is no loss of velocity after rebounding, the ball will rise to a height of
1 m
2 m
3 m
4 m