On a ladder resisting on a smooth ground and leaning against a rough vertical wall, the force of friction acts
Towards the wall at its upper end
Away from the wall at its upper end
Upwards at its upper end
Downwards at its upper end
Correct Answer :
C. Upwards at its upper end
Related Questions
The ratio of the moment of inertia of a rectangle about its centroidal axis to the moment of inertia about its base, is
1/4
1/2
3/4
2
On a ladder resisting on a smooth ground and leaning against a rough vertical wall, the force of friction acts
Towards the wall at its upper end
Away from the wall at its upper end
Upwards at its upper end
Downwards at its upper end
If the angular distance, 0 = 2t3 - 3t², the angular acceleration at t = 1 sec. is
1 rad/sec²
4 rad/sec²
6 rad/sec²
12 rad/sec²
The torque produced by a force depends on (i) The magnitude of the force (ii) The direction of the force (iii) The point of application of the force relative to origin The correct answer is
Only (i)
Both (i) and (ii)
Both (i) and (iii)
All (i), (ii) and (iii)
Minimum pull in a suspended cable with supports at two ends is equal to
Horizontal thrust
Support reactions
Resultant of horizontal thrust and support reaction
Half the weight of the cable
The piston of a steam engine moves with a simple harmonic motion. The crank rotates 120 r.p.m. and the stroke length is 2 metres. The linear velocity of the piston when it is at a distance of 0.5 metre from the centre, is
5.88 m/sec
8.88 m/sec
10.88 m/sec
12.88 m/sec
One end of a light string 4 m in length is fixed to a point on a smooth wall and the other end fastened to a point on the surface of a smooth sphere of diameter 2.25 m and of weight 100 kg. The tension in the string is
17.5 kg
19.5 kg
22.5 kg
25 kg
The necessary condition of equilibrium of a body is:
Algebraic sum of horizontal components of all the forces must be zero
Algebraic sum of vertical components of all the forces must be zero
Algebraic sum of the moments of the forces about a point must be zero
All (a), (b) and (c)
A simple pendulum of length 1 has an energy E when its amplitude is A. If its amplitude is increased to 2 A, the energy becomes
E
E/2
2E
4E
If the resultant of two forces has the same magnitude as either of the force, then the angle between the two forces is
30°
45°
60°
120°
A satellite moves in its orbit around the earth due to
Gravitational force
Centripetal force
Centrifugal force
None of these
Impulse can be obtained from a
Force-displacement diagram
Force-time diagram
Velocity-time diagram
Velocity-displacement diagram
A stone is thrown vertically upwards with a vertical velocity of 49 m/sec. It returns to the ground in
5 sec
8 sec
10 sec
20 sec
The ends of a string weighing w/metre are attached to two points at the same horizontal level. If the central dip is very small, the horizontal tension of the string throughout is
wl/4d
wl²/4d
wl²/8d
wl²/16d
Select the correct statement
The body centrode rolls on the space centrode
The space centrode rolls on the body centrode
Both body and space centrodes may role on each other
The body centrode never touches space centrode
A ball moving with a velocity of 5 m/sec impinges a fixed plane at an angle of 45° and its direction after impact is equally inclined to the line of impact. If the coefficient of restitution is 0.5, the velocity of the ball after impact will be
0.5 m/sec
1.5 m/sec
2.5 m/sec
3.5 m/sec
When a body of mass M1 is hanging freely and another of mass M2 lying on a smooth inclined plane(α) are connected by a light index tensile string passing over a smooth pulley, the acceleration of the body of mass M1, will be given by
g(M1 + M2 sin α)/(M1 + M2) m/sec
g(M1 - M2 sin α)/(M1 + M2) m/sec²
g(M2 + M1 sin α)/(M1 + M2) m/sec²
g(M2 × M1 sin α)/(M2 - M1) m/sec²
If a particle moves with a uniform angular velocity ω radians/sec along the circumference of a circle of radius r, the equation for the velocity of the particle, is
v = ω √(y² - r²)
y = ω √(y - r)
v = ω √(r² + y²)
v = ω √(r² - y²)
A cable loaded with 10 kN/m of span is stretched between supports in the same horizontal line 100 m apart. If the central dip is 10 m, then the maximum and minimum pull in the cable respectively are
1346.3 kN and 1500 kN
1436.2 kN and 1250 kN
1346.3 kN and 1250 kN
1436.2 kN and 1500 kN
If the tension in a cable supporting a lift moving upwards is twice the tension when the lift is moving downwards, the acceleration of the lift, is
g/2
g/3
g/4
g/5
If the linear velocity of a point on the rim of a wheel of 10 m diameter, is 50 m/sec, its angular velocity will be
20 rad/sec
15 rad/sec
10 rad/sec
5 rad/sec
The graphical method of determining the forces in the members of a truss is based on
Method of joint
Method of section
Either method
None of the two methods
When two forces, each equal to P, act at 90° to each other, then the resultant will be
P
P√2
P/√2
2P
The bending moment in an arch is proportional to
Vertical ordinate of funicular polygon
Vertical ordinate of the arch
Intercept between the arch axis and the funicular polygon
None of these
A circular disc rotates at n rpm. The angular velocity of a circular ring of same mass and radius as the disc and to have the same angular momentum is
n rpm
n/2 rpm
n/4 rpm
2n rpm
The maximum displacement of a particle executing S.H.M. corresponds to
Zero potential energy and maximum kinetic energy
Zero kinetic energy and maximum potential energy
Maximum kinetic energy and maximum potential energy
Minimum kinetic energy and minimum potential energy
One Joule is equivalent to
9.81 Newton metre
1 Newton metre
1 kg wt metre
1 dyne metre
Two loads of 50 kg and 75 kg are hung at the ends of a rope passing over a smooth pulley shown in below figure. The tension in the string is: 
50 kg
75 kg
25 kg
60 kg
Pick up the correct statement from the following. The kinetic energy of a body
Before impact is equal to that after impact
Before impact is less than that after impact
Before impact is more than that after impact
Remain constant
A 49 kg lady stands on a spring scale in an elevator. During the first 5 sec, starting from rest, the scale reads 69 kg. The velocity of the elevator will be
10 m/sec
15 m/sec
20 m/sec
25 m/sec