A ball moving on a smooth horizontal table hits a rough vertical wall, the coefficient of restitution between ball and wall being 1/3. The ball rebounds at the same angle. The fraction of its kinetic energy lost is
1/3
2/3
1/9
8/9
Correct Answer :
D. 8/9
Related Questions
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
If the horizontal range is 2.5 times the greatest height, the angle of projection of the projectile, is
57°
58°
59°
60°
The frequency of oscillation on moon as compared to that on earth, will be
2.44 times more
2.44 times less
3 times less
3 times more
For a self-locking machine, the efficiency should be
Less than 60%
50 %
More than 50%
None of these
If the angle between the applied force and the direction of motion of a body, is between 90° and 180°, the work done, is called
Virtual work
Imaginary work
Zero work
Negative work
The velocity of a body fallen from height h, on reaching the ground is given by
v = 2gh
v = 2gh2
v = √(2gh)
v = 1/√(2gh)
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
To double the period of oscillation of a simple pendulum
The mass of its bob should be doubled
The mass of its bob should be quadrupled
Its length should be quadrupled
Its length should be doubled
If the radius of the earth is 600 km the height of a mountain above sea level at the top of which a beat seconds pendulum at sea level, looses 27 seconds a day, is
500 metres
1000 metres
1500 metres
2000 metres
For the system of the loads shown in below figure, the time required for the 6.6 kg load to fall on the edge, is 
1 sec
2 sec
3 sec
4 sec
Varingons theorem of moments states
Arithmetical sum of the moments of two forces about any point, is equal to the moments of their resultant about that point
Algebraic sum of the moments of two forces about any point, is equal to the moment of their resultant about that point
Arithmetical sum of the moments of the forces about any point in their plane, is equal to the moment of their resultant about that point
Algebraic sum of the moments of the forces about any point in their plane, is equal to the moment of their resultant about that point
When a body in equilibrium undergoes an infinitely small displacement, work imagined to be done, is known as
Imaginary work
Negative work
Virtual work
None of these
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
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 square hole is made in a circular lamina, the diagonal of the square is equal to the radius of the circle as shown in below figure the shift in the centre of gravity is 
r (π - 0.75)/(π - 0.5)
r (π - 0.25)/(π - 0.75)
r (π - 0.5)/(π - 0.75)
r (π - 0.5)/(π - 0.25)
It is observed that in a certain sinusoidal oscillation, the amplitude is linearly dependent on the frequency f. If the maximum velocity during the oscillation is V, then V must be proportional to
f
1/f
1/f²
f²
μ is coefficient of friction. A wheeled vehicle travelling on a circular level track will slip and overturn simultaneously if the ratio of its wheel distance to the height of its centroid, is
μ
2μ
3μ
½μ
A rod 5 m in length is moving in a vertical plane. When it is inclined at 60° to horizontal, its lower end is moving horizontally at 3 m/sec and upper end is moving in vertical direction. The velocity of its upper end, is
0.5 m/sec
1.0 m/sec
1.5 m/sec
2.5 m/sec
Total no of instantaneous centres of a machine having n links, is
n/2
n
(n - 1)
n (n - 1)/2
Engineer's units of force, is
Newton in absolute units
Dyne in absolute units
Newton and dyne in absolute units
All the above
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)
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
A projectile is fired with a velocity of 100.3 m/sec. at an elevation of 60°. The velocity attained by the projectile when it is moving at a height of 100 m, is
70 m/sec
75 m/sec
80 m/sec
90 m/sec
One Joule is equivalent to
9.81 Newton metre
1 Newton metre
1 kg wt metre
1 dyne metre
A satellite goes on moving along its orbit round the earth due to
Gravitational force
Centrifugal force
Centripetal force
None of these
The intrinsic equation of catenary is
S = c tan ψ
y = c cosh x/c
y = c cosh ψ
y = c sinh ψ
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
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
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
A funicular polygon cannot be made to pass through
One specified point
Two specified points
Three specified points
More than three specified points