On the ladder resting on the ground and leaning against a smooth vertical wall, the force of friction will be
Downwards at its upper end
Upwards at its upper end
Perpendicular to the wall at its upper end
Zero at its upper end
Correct Answer :
D. Zero at its upper end
Related Questions
The unit of force in S.I. units is
kilogram
Newton
Watt
Dyne
The efficiency of a lifting machine is the ratio of
Output to the input
Work done by the machine to the work done on the machine
Mechanical advantage to the velocity ratio
All of the above
Moment of inertia of a circular section about its diameter (d) is
πd3/16
πd3/32
πd4/32
πd4/64
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
When a body falls freely under gravitational force, it possesses __________ weight.
No
Minimum
Maximum
None of these
Angle of friction is the
Angle between normal reaction and the resultant of normal reaction and the limiting friction
Ratio of limiting friction and normal reaction
The ratio of minimum friction force to the friction force acting when the body is just about to move
The ratio of minimum friction force to friction force acting when the body is in motion
Tension in the cable supporting a lift is more when the lift is moving __________ with an acceleration.
Upwards
Downwards
Horizontal
None of these
The linear velocity of a body rotating at ω rad/s along a circular path of radius r is given by
ω/r
ω.r
ω2/r
ω2.r
The maximum velocity of a particle moving with simple harmonic motion is
ω
ωr
ω2r
ω/r
Tangent of angle of friction is equal to
Kinetic friction
Limiting friction
Angle of repose
Coefficient of friction
The overturning of a vehicle on a level circular path can be avoided if the velocity of vehicle is __________ √(gra/h)
Less than
Greater than
Equal to
None of these
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
The range of projectile will be maximum for a given velocity of projectile, when the angle of projection (α) is
β/2
30° + β/2
45° + β/2
60° + β/2
The moment of inertia of a rectangular section 3 cm wide and 4 cm deep about X-X axis is
9 cm4
12 cm4
16 cm4
20 cm4
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
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
The moment of the force P about O as shown in the below figure is 
P × OA
P × OB
P × OC
P × AC
Effect of a force on a body depends upon
Magnitude
Direction
Position or line of action
All of the above
The potential energy of a vertically raised body is __________ the kinetic energy of a vertically falling body.
Equal to
Less than
Greater than
None of these
The unit of angular acceleration is
N-m
m/s
m/s2
rad/s2
Moment of inertia of a rectangular section having width (b) and depth (d) about an axis passing through its C.G. and parallel to the width (b), is
db³/12
bd³/12
db³/36
bd³/36
In a framed structure, as shown in the below figure, the force in the member AB is __________ the force in member AC. 
Half
Equal to
Double
None of these
A couple produces
Translatory motion
Rotational motion
Combined translatory and rotational motion
None of the above
The force applied on a body of mass 100 kg to produce an acceleration of 5 m/s2, is
20 N
100 N
500 N
None of these
If a number of forces are acting at a point, their resultant is given by
(ΣV)2 + (ΣH)2
√[(ΣV)2 + (ΣH)2]
(ΣV)2 +(ΣH)2 +2(ΣV)(ΣH)
√[(ΣV)2 +(ΣH)2 +2(ΣV)(ΣH)]
Which of the following statement is correct?
The periodic time of a particle moving with simple harmonic motion is the time taken by a particle for one complete oscillation.
The periodic time of a particle moving with simple harmonic motion is directly proportional to its angular velocity.
The velocity of the particle moving with simple harmonic motion is zero at the mean position.
The acceleration of the particle moving with simple harmonic motion is maximum at the mean position.
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 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)
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 resultant of the following three couples 20 kg force, 0.5 m arm, +ve sense 30 kg force, 1 m arm, -ve sense 40 kg force, 0.25 m arm, +ve sense having arm of 0.5 m will be
20 kg, -ve sense
20 kg, + ve sense
10 kg, + ve sense
10 kg, -ve sense