The C.G. of a hemisphere from its base measured along the vertical radius is at a distance of
4R/3π
3R/8
3πR/4
8R/3
Correct Answer :
B. 3R/8
Related Questions
If two forces of 3 kg and 4 kg act at right angles to each other, their resultant force will be equal to
7 kg
1 kg
5 kg
None of these
The member forces in a statically in determinate truss
Can be obtained by graphic statics
Cannot be obtained by graphic statics
May be obtained by graphic statics
Can be obtained by graphic statics by trial and error
The velocity ratio of an inclined plane of inclination θ with horizontal for lifting a load is
sin θ
cos θ
tan θ
cosec θ
The ratio of the speed of a rolling cylinder to the speed of sliding cylinder is
Less than 1
Equal to 1
Between 1 and 2
Greater than 2
0.For maximum range of a projectile, the angle of projection should be
30°
45°
60°
None of these
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)
The time period of a simple pendulum depends on (i) Mass of suspended particle (ii) Length of the pendulum (iii) Acceleration due to gravity The correct answer is
Only (i)
Both (ii) and (iii)
Both (i) and (iii)
All are correct
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
Work may be defined as
Force × distance
Force × velocity
Force × acceleration
None of these
Periodic time of a particle moving with simple harmonic motion is the time taken by the particle for
Half oscillation
Quarter oscillation
Complete oscillation
None of these
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
If the kinetic energy and potential energy of a simple harmonic oscillator of amplitude A are both equal to half the total energy, then the displacement is equal to
A
A/2
A/√2
A√2
The direction of projection should bisect the angle between the inclined plane and the vertical for a range of a projectile on inclined plane
To be zero
To be maximum
To be minimum
None of these
Two forces of 6 Newtons and 8 Newtons which are acting at right angles to each other, will have a resultant of
5 Newtons
8 Newtons
10 Newtons
12 Newtons
Minimum potential energy of a system will be in the position of
Stable equilibrium
Unstable equilibrium
Neutral equilibrium
All of the above
A body of weight 14 g appears to weight 13 g when weighed by a spring balance in a moving lift. The acceleration of the lift at that moment was
0.5 m/sec2
0.7 m/sec2
1 m/sec2
1 cm/sec2
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
A heavy ladder resting on floor and against a vertical wall may not be in equilibrium if
Floor is smooth and wall is rough
Floor is rough and wall is smooth
Both floor and wall are rough
Both floor and wall are smooth
The ratio of the ranges on the inclined plane with motion upward and with motion downward for a given velocity, angle of projection will be
sin (α + β)/sin (α - β)
sin (α - β)/sin (α + β)
cos (α - β)/cos (α + β)
tan (α - β)/tan (α + β)
A satellite is said to move in a synchronous orbit if it moves at an altitude of 36, 000 km with a maximum velocity of about
7000 km per hour
8000 km per hour
9000 km per hour
11,000 km per hour
The following is in unstable equilibrium
A uniform solid cone resting on a generator on a smooth horizontal plane
A uniform solid cone resting on its base on a horizontal plane
A solid cube resting on one edge
A satellite encircling the earth
The moment of inertia of a hollow circular section whose external diameter is 8 cm and internal diameter is 6 cm, about centroidal axis, is
437.5 cm4
337.5 cm4
237.5 cm4
137.5 cm4
The centre of gravity of a trapezoidal dam section whose top width is a, bottom width is band the vertical side is a, from its vertical face is
(a² + ab + b²)/3 (a + b)
(b² + bc + c²)/3 (b + c)
(a² + ab + c²)/3 (a + c)
None of these
Two circular discs of same weight and thickness are made from metals having different densities. Which disc will have the larger rotational inertia about its central axis?
Disc with larger density
Disc with smaller density
Both discs will have same rotational inertia
None of the above
A body of weight w placed on an inclined plane is acted upon by a force P parallel to the plane which causes the body just to move up the plane. If the angle of inclination of the plane is θ and angle of friction is φ, the minimum value of P, is
w sin (φ - θ)/cos φ
w sin (θ - φ)/cos φ
w cos (θ + φ)/cos φ
w sinθ cos(θ - φ)/sin φ
For perfectly elastic bodies, the value of coefficient of restitution is
Zero
0.5
1.0
Between 0 and 1
A particle moves in a straight line and its position is defined by the equation x = 6 t² - t3 where t is expressed in seconds and x in meters. The maximum velocity during the motion is
6 m/sec
12 m/sec
24 m/sec
48 m/sec
On a mass m describing a circular path of radius r, the centrifugal force
Acts tangentially to the circular path
Acts towards the centre of rotation
Acts away from the centre of rotation
Is mw2r/g kgf
Cartesian form of the equation of catenary is
y = c cosh x/c
y = c sinh x/c
y = c tan x/c
y = c sin x/c
On a ladder resting on a rough ground and leaning against a smooth vertical wall, the force of friction acts
Downwards at its upper end
Upwards at its upper end
Perpendicular to the wall at its upper end
Zero at its upper end