The friction experienced by a body, when in motion, is known as
Rolling friction
Dynamic friction
Limiting friction
Static friction
Correct Answer :
B. Dynamic friction
Related Questions
The centre of gravity of an isosceles triangle with base (p) and sides (q) from its base is
[√(4p² - q²)]/6
(4p² - q²)/6
(p² - q²)/4
(p² + q²)/4
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
The motion of a particle round a fixed axis is
Translatory
Rotary
Circular
Translatory as well as rotary
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
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
Moment of inertia of a triangular section of base (b) and height (h) about an axis through its base, is
bh3/4
bh3/8
bh3/12
bh3/36
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
The moment of inertia of a thin spherical shell of mass m and radius r, about its diameter is
mr2/3
2mr2/3
2mr2/5
3mr2/5
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
One end of a helical spring is fixed while the other end carries the load W which moves with simple harmonic motion. The frequency of motion is given by (where δ = Deflection of the spring.)
2π. √(g/δ)
1/2π. √(g/δ)
2π. √(δ/g)
1/2π. √(δ/g)
The rate of change of displacement of a body is called
Velocity
Acceleration
Momentum
None of these
If three forces acting in different planes can be represented by a triangle, these will be in
Non-equilibrium
Partial equilibrium
Full equilibrium
Unpredictable
The static friction
Bears a constant ratio to the normal reaction between the two surfaces
Is independent of the area of contact, between the two surfaces
Always acts in a direction, opposite to that in which the body tends to move
All of the above
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
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
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
If n = number of members and y = number of joints, then for a perfect frame, n = ?
1/2
2/3
3/2
2/4
Which of the following is not the unit of distance?
Angstrom
Light year
Micron
Milestone
The ideal angle of banking provided on the curves on roads depends upon
Weight of the vehicle
(Velocity)2 of the vehicle
Nature of the road surface
Coefficient of friction between the road and vehicle contact point
When a body falls freely under gravitational force, it possesses __________ weight.
No
Minimum
Maximum
None of these
A machine having an efficiency less than 50%, is known as
Reversible machine
Non-reversible machine
Neither reversible nor non-reversible machine
Ideal machine
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
A framed structure is imperfect, if the numbers of members are __________ (2j - 3).
Equal to
Less than
Greater than
Either (B) or (C)
The C.G. of a plane lamina will not be at its geometrical centre in the case of a
Right angled triangle
Equilateral triangle
Square
Circle
The range of projectile (R) on an upward inclined plane is
g. cos² β/2u². sin (α + β). cos α
2u². sin (α + β). cos α/g. cos² β
g. cos² β/2u². sin (α - β). cos α
2u². sin (α - β). cos α/g. cos² β
Two balls of equal mass and of perfectly elastic material are lying on the floor. One of the balls with velocity v is made to strike the second ball. Both the balls after impact will move with a velocity
v
v/2
v/4
v/8
Three forces acting on a rigid body are represented in magnitude, direction and line of action by the three sides of a triangle taken in order. The forces are equivalent to a couple whose moment is equal to
Area of the triangle
Twice the area of the triangle
Half the area of the triangle
None of these
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
A smooth cylinder lying on a __________ is in neutral equilibrium.
Curved surface
Convex surface
Horizontal surface
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