A uniform rod 9 m long weighing 40 kg is pivoted at a point 2 m from one end where a weight of 120 kg is suspended. The required force acting at the end in a direction perpendicular to rod to keep it equilibrium, at an inclination 60° with horizontal, is
40 kg
60 kg
10 kg
100 kg
Correct Answer :
C. 10 kg
Related Questions
The maximum pull in a cable, carrying a uniformly distributed load and supported at two ends which are at the same level, is at
Supports
Quarter span
Mid span
None of the above
If the given forces P₁, P₂, P₃ and P₄ are such that the force polygon does not close, then the system will
Be in equilibrium
Always reduce to a resultant force
Always reduce to a couple
Both (A) and (C)
Total no of instantaneous centres of a machine having n links, is
n/2
n
(n - 1)
n (n - 1)/2
A ball is dropped from a height of 16 m on a horizontal floor. If it rebounds to a height of 9 m after striking the floor, the coefficient of restitution between ball and floor is
1/4
2/3
3/4
4/3
The centre of gravity of a plane lamina will not be at its geometrical centre if it is a
Circle
Equilateral triangle
Rectangle
Right angled triangle
A disc of mass 4 kg, radius 0.5 m and moment of inertia 3 kgm² rolls on a horizontal surface so that its center moves with speed 5 m/see. Kinetic energy of the disc is
50 J
150 J
200 J
400 J
Coefficient of friction depends on
Nature of surfaces only
Area of contact only
Both (A) and (B)
None of the above
A bullet weighing 200 g is fired horizontally with a velocity of 25 m/sec from a gun carried on a carriage which together with the gun weighs 100 kg. The velocity of recoil of the gun, will be
0.01 m/sec
0.05 m/sec
1.00 m/sec
1.5 m/see
The characteristic of a couple is:
Algebraic sum of forces, constituting a couple is zero
Algebraic sum of moments of forces, constituting a couple, about any point, is same
A couple can be never the balanced by a single force
All the above
A system of coplanar forces is in equilibrium when
Force polygon closes
Funicular polygon closes
Both force polygon and funicular polygon close
All the forces are concurrent
One Newton force, is
103 dynes
104 dynes
105 dynes
106 dynes
If a body is acted upon by a number of coplanar non-concurrent forces, it may
Rotate about itself without moving
Move in any one direction
Move in any one direction rotating about itself
All the above
Two shots fired simultaneously from the top and bottom of a vertical tower with elevations of 30° and 45° respectively strike a target simultaneously. If horizontal distance of the target from the tower is 1000 m, the height of the tower is
350 m
375 m
400 m
425 m
According to Law of Triangle of Forces
Three forces acting at a point, can be rep-resented by the sides of a triangle, each side being in proportion to the force
Three forces acting along the sides of a triangle are always in equilibrium
If three forces acting on a, point can be represented in magnitude and direction, by the sides of a triangle taken in order, these will be in equilibrium
If the forces acting on a particle be represented in magnitude and direction by the two sides of a triangle taken in order, their resultant will be represented in magnitude and direction by the third side of the triangle, taken in opposite order
A particle is executing simple harmonic motion in a line 1.0 m long. If the time of one complete vibration is 1 sec, then the maximum velocity of the particle is
1.00 m/sec
1.57 m/sec
3.14 m/sec
6.28 m/sec
A projectile is thrown at an angle α to the horizontal with velocity v. It will have the maximum centripetal acceleration
At the start
At the top of the trajectory
As it strikes the ground
Elsewhere
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°
The condition of equilibrium for any system of forces in a plane is
That polygon of forces must close
That resultant couple must be zero
Both (A) and (B)
None of the above
The inherent property of a body which offers reluctance to change its state of rest or uniform motion, is
Weight
Mass
Inertia
Momentum
The reaction at the support D of the continuous beam ABCD, hinged at two points shown in below figure is 
1.6 t
1.6 t ↓
0.5 t
0.5 t ↓
The resultant of the forces acting on a body will be zero if the body
Rotates
Moves with variable velocity in a straight line
Moves along a curved path
Does not move at all
For a particle moving with a simple harmonic motion, the frequency is
Directly proportional to periodic time
Inversely proportional to periodic time
Inversely proportional to its angular velocity
Directly proportional to its angular velocity
The tension in a cable supporting a lift
Is more when the lift is moving downwards
Is less when the lift is moving upwards
Remains constant whether its moves downwards or upwards
Is less when the lift is moving downwards
The shape of a suspended cable for a uniformly distributed load over it is
Circular
Parabolic
Catenary
Cubic parabola
A weight of 100 kg is supported by a string whose ends are attached to pegs A and B at the same level shown in below figure. The tension in the string is 
50 kg
75 kg
100 kg
120 kg
A string of length 90 cm is fastened to two points A and B at the same level 60 cm apart. A ring weighing 120 g is slided on the string. A horizontal force P is applied to the ring such that it is in equilibrium vertically below B. The value of P is:
40 g
60 g
80 g
100 g
A rigid body suspended vertically at a point and oscillating with a small amplitude under the action of the force of gravity, is called
Simple pendulum
Compound pendulum
Second's pendulum
None of these
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
Pick up the correct statement from the following:
Nature plays an important role in the launch of a satellite
The earth's gravity reduces the speed of a satellite by 32 km per second
The gravitational force relents as the satellite climbs higher
All the above
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