Frictional force encountered after commencement of motion is called
Limiting friction
Kinematic friction
Frictional resistance
Dynamic friction
Correct Answer :
D. Dynamic friction
Related Questions
In order to double the period of simple pendulum, the length of the string should be
Halved
Doubled
Quadrupled
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 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
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 skidding away of the vehicle on a level circular path can be avoided if the force of friction between the wheels and the ground is __________ the centrifugal force.
Less than
Greater than
Equal to
None of these
The mechanical advantage of a lifting machine is the ratio of
Distance moved by effort to the distance moved by load
Load lifted to the effort applied
Output to the input
All of the above
The bellow figure shows the two equal forces at right angles acting at a point. The value of force R acting along their bisector and in opposite direction is 
P/2
2P
√2 × P
P/√2
Two coplanar couples having equal and opposite moments
Balance each other
Produce a couple and an unbalanced force
Are equivalent
Cannot balance each other
Which of the following is not the unit of energy?
kg m
kcal
Watt
Watt hours
The time of flight (t) of a projectile on an upward inclined plane is (where u = Velocity of projection, α = Angle of projection, and β = Inclination of the plane with the horizontal.)
t = g cos β/2u sin (α - β)
t = 2u sin (α - β)/g cos β
t = g cos β/2u sin (α + β)
t = 2u sin (α + β)/g cos β
One watt is equal to
0.1 joule/s
1 joule/s
10 joules/s
100 joules/s
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 forces which meet at one point, but their lines of action __________ on the same plane, are Known as non-coplanar concurrent forces.
Lie
Do not lie
Either A or B
None of these
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 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
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
The centre of percussion of the homogeneous rod of length L suspended at the top will be
L/2
L/3
3L/4
2L/3
Coulomb friction is the friction between
Bodies having relative motion
Two dry surfaces
Two lubricated surfaces
Solids and liquids
According to Newton's first law of motion,
Everybody continues in its state of rest or of uniform motion, in a straight line, unless it is acted upon by some external force
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
To every action, there is always an equal and opposite reaction
None of the above
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 unit of force in S.I. system of units is
Dyne
Kilogram
Newton
Watt
The bodies which rebound after impact are called
Inelastic bodies
Elastic bodies
Neither elastic nor inelastic bodies
None of these
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 energy possessed by a body, for doing work by virtue of its position, is called
Potential energy
Kinetic energy
Electrical energy
Chemical energy
The equivalent length of a simple pendulum which gives the same frequency as compound pendulum is
h/(kG² + h²)
(kG² + h²)/h
h²/(kG² + h²)
(kG² + h²)/h²
The moment of inertia of a thin rod of mass m and length l, about an axis through its centre of gravity and perpendicular to its length is
ml2/4
ml2/ 6
ml2/8
ml2/12
The power developed by a body acted upon by a torque T Newton metre (N - m) and revolving at ω radian/s is given by
T.ω (in watts)
T.ω/60 (in watts)
T.ω/75 (in kilowatts)
T.ω/4500 (in kilowatts)
The resolved part of the resultant of two forces inclined at an angle θ in a given direction is equal to
The algebraic sum of the resolved parts of the forces in the given direction
The sum of the resolved parts of the forces in the given direction
The difference of the forces multiplied by the cosine of θ
The sum of the forces multiplied by the sine of θ
Moment of inertia of a triangular section of base (b) and height (h) about an axis passing through its C.G. and parallel to the base, is
bh3/4
bh3/8
bh3/12
bh3/36
Effect of a force on a body depends upon
Magnitude
Direction
Position or line of action
All of the above