Pick up the incorrect statement from the following:
The C.G. of a circle is at its centre
The C.G. of a triangle is at the intersection of its medians
The C.G. of a rectangle is at the intersection of its diagonals
The C.G. of a semicircle is at a distance of r/2 from the centre
Correct Answer :
D. The C.G. of a semicircle is at a distance of r/2 from the centre
Related Questions
The velocity ratio for the third system of pulleys is
n
n²
2n
2n - 1
A body of weight W is required to move up on rough inclined plane whose angle of inclination with the horizontal is α. The effort applied parallel to the plane is given by (where μ = tanφ = Coefficient of friction between the plane and the body.)
P = W tanα
P = W tan (α + φ)
P = W (sinα + μcosα)
P = W (cosα + μsinα)
If a number of forces act simultaneously on a particle, it is possible
Not a replace them by a single force
To replace them by a single force
To replace them by a single force through C.G.
To replace them by a couple
Two like parallel forces are acting at a distance of 24 mm apart and their resultant is 20 N. It the line of action of the resultant is 6 mm from any given force, the two forces are
15 N and 5 N
20 N and 5 N
15 N and 15 N
None of these
The coefficient of friction depends upon
Nature of surfaces
Area of contact
Shape of the surfaces
All of the above
The unit of angular acceleration is
N-m
m/s
m/s2
rad/s2
A single force and a couple acting in the same plane upon a rigid body
Balance each other
Cannot balance each other
Produce moment of a couple
Are equivalent
The forces, which meet at one point and their lines of action also lie on the same plane, are known as
Coplanar concurrent forces
Coplanar non-concurrent forces
Non-coplanar concurrent forces
Non-coplanar non-concurrent forces
The time of flight of a projectile on downward inclined plane depends upon
Angle of projection
Angle of inclination of the plane
Both (A) and (B)
None of these
Non-coplanar concurrent forces are those forces which
Meet at one point, but their lines of action do not lie on the same plane
Do not meet at one point and their lines of action do not lie on the same plane
Meet at one point and their lines of action also lie on the same plane
Do not meet at one point, but their lines of action lie on the same plane
A cable with a uniformly distributed load per horizontal meter run will take the following shape
Straight line
Parabola
Hyperbola
Elliptical
The C.G. of a right circular solid cone of height h lies at the following distance from the base
h/2
J/3
h/6
h/4
According to law of triangle of forces
Three forces acting at a point will be in equilibrium
Three forces acting at a point can be represented by a triangle, each side being proportional to force
If three forces acting upon a particle are represented in magnitude and direction by the sides of a triangle, taken in order, they will be in equilibrium
If three forces acting at a point are in equilibrium, each force is proportional to the sine of the angle between the other two
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 length of a second's pendulum is
94.9 cm
99.4 cm
100 cm
101 cm
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
From a circular plate of diameter 6 cm is cut out a circle whose diameter is a radius of the plate. Find the e.g. of the remainder from the centre of circular plate
0.5 cm
1.0 cm
1.5 cm
2.5 cm
An ideal machine is one whose efficiency is
Between 60 and 70 %
Between 70 and 80 %
Between 80 and 90 %
100 %
The matter contained in a body, is called
Impulsive force
Mass
Weight
Momentum
In actual machines, mechanical advantage is __________ velocity ratio.
Equal to
Less than
Greater than
None of these
The total momentum of a system of masses (i. e. moving bodies) in any one direction remains constant, unless acted upon by an external force in that direction. This statement is called
Newton's first law of motion
Newton's second law of motion
Principle of conservation of energy
Principle of conservation of momentum
Which is the correct statement about law of polygon of forces?
If any number of forces acting at a point can be represented by the sides of a polygon taken in order, then the forces are in equilibrium
If any number of forces acting at a point can be represented in direction and magnitude by the sides of a polygon, then the forces are in equilibrium
If a polygon representing forces acting at a point is closed then forces are in equilibrium
If any number of forces acting at a point can be represented in direction and magnitude by the sides of a polygon taken in order, then the forces are in equilibrium
The range of projectile on a downward inclined plane is ________ the range on upward inclined plane for the same velocity of projection and angle of projection.
Less than
More than
Equal to
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
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
In the shown figure, if the angle of inclination of the plane is increased, then acceleration of the system will 
Increase
Decrease
Remain the same
None of these
For any system of coplanar forces, the condition of equilibrium is that the
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
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
Which of the following statement is correct?
The algebraic sum of the forces, constituting the couple is zero
The algebraic sum of the forces, constituting the couple, about any point is the same
A couple cannot be balanced by a single force but can be balanced only by a couple of opposite sense
All of the above
Which of the following is the example of lever of first order?
Arm of man
Pair of scissors
Pair of clinical tongs
All of the above