The force polygon representing a set of forces in equilibrium is a
Triangle
Open polygon
Closed polygon
Parallelogram
Correct Answer :
C. Closed polygon
Related Questions
Centre of gravity of a thin hollow cone lies on the axis of symmetry at a height of
One-half of the total height above base
One-third of the total height above base
One-fourth of the total height above base
None of these
The gravitational force makes a satellite go round the earth in a circular orbit, if it is projected with an initial velocity of
8.04 km/sec at a height of 285 km
11.11 km/sec at a height of 37,400 km
11.26 km/sec, the satellite escapes the pull of the earth
All the above
A particle moves with a velocity of 2 m/sec in a straight line with a negative acceleration of 0.1 m/sec2. Time required to traverse a distance of 1.5 m, is
40 sec
30 sec
20 sec
15 sec
The reaction at the support A of the beam shown in below figure is 
2 t
5.8 t
0.2 t
3.5 t
Work may be defined as
Force × distance
Force × velocity
Force × acceleration
None of these
u1 and u2 are the velocities of approach of two moving bodies in the same direction and their corresponding velocities of separation are v1 and v2. As per Newton's law of collision of elastic bodies, the coefficient of restitution (e) is given by
e = v1 - v2/u2 - u1
e = u2 - u1/v1 - v2
e = v2 - v1/u1 - u2
e = v1 - v2/u2 + u1
If the velocity of projection is 4 m/sec and the angle of projection is α°, the maximum height of the projectile from a horizontal plane, is
u² cos² α/2g
u² sin² α/2g
u² tan² α/2g
u² sin 2α/2g
Which of the following represents the state of neutral equilibrium?
A cube resting on one edge
A smooth cylinder lying on a curved surface
A smooth cylinder lying on a convex surface
None of the above
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
Rate of change of angular momentum is equal to
Force
Torque
Linear momentum
Impulse
A geo-stationary satellite is one which orbits the earth with a velocity of rotation of
Moon
Earth
Sun
Pole
A light rope is loaded with many equal weights at equal horizontal intervals. The points of suspension on the rope lie on a
Parabola
Catenary
Cycloid
Ellipse
A force P of 50 N and another force Q of unknown magnitude act at 90° to each other. They are balanced by a force of 130 N. The magnitude of Q is
60 N
80 N
100 N
120 N
A vehicle weighing w kg is to run on a circular curve of radius r. If the height of its centre of gravity above the road level is h and the distance between the centres of wheels is 2a, the maximum velocity, in order to avoid over turning, will be
gra/h
√(gra/h)
3√(gra/h)
4√(gra/h)
A Second's pendulum gains 2 minutes a day. To make it to keep correct time its length
Must be decreased
Must be increased
Is not changed but weight of the bob is increased
Is not changed but weight of the bob is decreased
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
The unit of rotational inertia of a body in C.G.S system is
cm4
kg.cm²
gm.cm²
gm.cm3
The C.G. of a right circular cone lies on its axis of symmetry at a height of
h/2
h/3
h/4
h/5
The angles between two forces to make their resultant a minimum and a maximum respectively are
0° and 90°
180° and 90°
90° and 180°
180° and 0°
In a simple screw jack, the pitch of the screw is 9 mm and length of the handle operating the screw is 45 cm. The velocity ratio of the system is
1.5
5
25
314
If α is the angular acceleration of a compound pendulum whose angular displacement is θ, the frequency of the motion is
2π √(α/θ)
(1/2π) √(α/θ)
4π √(α/θ)
2π √(α - θ)
For a self-locking machine, the efficiency should be
Less than 60%
50 %
More than 50%
None of these
The point about which combined motion of rotation and translation of a rigid body takes place, is known as
Virtual centre
Instantaneous centre
Instantaneous axis
Point of rotation
The acceleration of a particle moving along the circumference of a circle with a uniform speed, is directed
Radially
Tangentially at that point
Away from the centre
Towards the centre
Pick up the correct statement from the following:
If two equal and perfectly elastic smooth spheres impinge directly, they interchange their velocities
If a sphere impinges directly on an equal sphere which is at rest, then a fraction ½(1 - e2) the original kinetic energy is lost by the impact
If two equal spheres which are perfectly elastic impinge at right angles, their direction after impact will still be at right angles
All the above
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 uniform pyramid and a uniform prism of same height lie with their base on the surface. Which is more stable?
Pyramid
Prism
Both equally stable
None of the above
The angular speed of a car taking a circular turn of radius 100 m at 36 km/hr will be
0.1 rad/sec
1 rad/sec
10 rad/sec
100 rad/sec
From the circular plate of a diameter 6 cm is cut out a circular plate whose diameter is equal to radius of the plate. The C.G. of the remainder shifts from the original position through
0.25 cm
0.50 cm
0.75 cm
1.00 cm
A system of coplanar forces acting on a rigid body can be reduced to
One force only
One couple only
One force and one couple only
None of the above