According to the law of moments, 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.
Correct Answer :
C. The algebraic sum of their moments about any point in their plane is zero
Related Questions
The maximum velocity of a particle moving with simple harmonic motion is
ω
ωr
ω2r
ω/r
If a number of coplanar forces acting at a point be in equilibrium, the sum of clockwise moments must be __________ the sum of anticlockwise moments, about any point.
Equal to
Less than
Greater than
None of these
The total motion possessed by a body, is called
Impulsive force
Mass
Weight
Momentum
Non-coplanar non-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
Do not meet at one point but their lines of action lie on the same plane
None of the above
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
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
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
A smooth cylinder lying on its convex surface remains in __________ equilibrium.
Stable
Unstable
Neutral
None of these
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
The unit of moment of inertia of an area is
kg-m2
kg-m-s2
kg/m2
m4
When a body of mass m attains a velocity v from rest in time t, then the kinetic energy of translation is
mv2
mgv2
0.5 mv2
0.5 mgv2
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)
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)
The coefficient of restitution for inelastic bodies is
Zero
One
Between zero and one
More than one
A weight of 1000 N can be lifted by an effort of 80 N. If the velocity ratio is 20, the machine is
Reversible
Non-reversible
Ideal
None of these
Which of the following statement is correct in connection with projectiles?
A path, traced by a projectile in the space, is known as trajectory.
The velocity, with which a projectile is projected, is known as the velocity of projection.
The angle, with the horizontal, at which a projectile is projected, is known as angle of projection.
All of the above
The resultant of the two forces P and Q is R. If Q is doubled, the new resultant is perpendicular to P. Then
P = Q
Q = R
Q = 2R
None of these
The units of moment of inertia of mass are
kg-m²
m²/kg.
kg/m²
kg/m
One joule means that
Work is done by a force of 1 N when it displaces a body through 1 m
Work is done by a force of 1 kg when it displaces a body through 1 m
Work is done by a force of 1 dyne when it displaces a body through 1 cm
Work is done by a force of 1 g when it displaces a body through 1 cm
A framed structure, as shown in the below figure, is a 
Perfect frame
Deficient frame
Redundant frame
None of the above
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
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
Center of percussion is
The point of C.G.
The point of metacenter
The point of application of the resultant of all the forces tending to cause a body to rotate about a certain axis
Point of suspension
A body will begin to move down an inclined plane if the angle of inclination of the plane is _________ the angle of friction.
Equal to
Less than
Greater than
None of these
The resultant of two equal forces P making an angle θ, is given by
2P sinθ/2
2P cosθ/2
2P tanθ/2
2P cotθ/2
The centre of gravity of a semi-circle lies at a distance of __________ from its base measured along the vertical radius.
3r/ 8
4r/ 3π
8r/3
3r/4π
A ladder is resting on a smooth ground and leaning against a rough vertical wall. The force of friction will act
Towards the wall at its upper end
Away from the wall at its upper end
Downward at its upper end
Upward at its upper end
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)
The maximum mechanical advantage of a lifting machine is
1 + m
1 - m
1 / m
m