A marble ball is rolled on a smooth floor of a room to hit a wall. If the time taken by the ball in returning to the point of projection is twice the time taken in reaching the wall, the coefficient of restitution between the ball and the wall, is
0.25
0.50
0.75
1.0
Correct Answer :
B. 0.50
Related Questions
A particle is dropped from a height of 3 m on a horizontal floor, which has a coefficient of restitution with the ball of 1/2. The height to which the ball will rebound after striking the floor is
0.5 m
0.75 m
1.0 m
1.5 m
Power can be expressed as
Work/energy
Work/time
Work × time
Work/distance
The apparent weight of a man in a moving lift is less than his real weight when it is going down with
Uniform speed
An acceleration
Linear momentum
Retardation
If two forces are in equilibrium, then the forces must (i) Be equal in magnitude (ii) Be opposite in sense (iii) Act along the same line The correct answer is
(i) and (ii)
(i) and (iii)
Only (i)
All (i), (ii) and (iii)
In the structure shown in below figure, the member which carries zero force, is 
AB
BC
BE
All the above
A shell of mass 100 kg travelling with a velocity of 10 m/sec breaks into two equal pieces during an explosion which provides an extra kinetic energy of 20000 Joules. If the pieces continue to move in the same direction as before, then the speed of the faster one must be
20 m/sec
30 m/sec
40 m/sec
50 m/sec
According to Kennedy's theorem, if three bodies have plane motions, their instantaneous centres lie on
A point
A straight line
Two straight lines
A triangle
A number of forces acting simultaneously on a particle of a body
May not be replaced by a single force
May be replaced by a single force
May be replaced by a single force through C.G. of the body
May be replaced by a couple
Moment of inertia of a squares of side b about an axis through its centre of gravity, is
b3/4
b4/12
b4/3
b4/8
The mechanical advantage of an ideal machine is 100. For moving the local through 2 m, the effort moves through
0.02 m
2 m
2.5 m
20 m
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 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
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
Pick up the incorrect statement from the following. In case of suspension bridge due to rise in temperature,
Dip of the cable increases
Length of the cable increases
Dip of the cable decreases
None of these
The diagram showing the point of application and line of action of forces in their plane is called
Vector diagram
Space diagram
Force diagram
Funicular diagram
Which of the following is a scalar quantity?
Energy
Momentum
Torque
Impulse
Rate of change of angular momentum is equal to
Force
Torque
Linear momentum
Impulse
In a simple harmonic motion, the position of equilibrium is always
Stable
Unstable
Neutral
None of the above
The motion of a particle moving with S.H.M. from an extremity to the other, constitutes
Half an oscillation
One full oscillation
Two oscillations
None of these
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)
The unit of moments in M.K.S system, is
kg.m
kg/m2
kg/sec2
kg/sec
If the direction of projection bisects the angle between the vertical and the inclined plane, then the range of projectile on the inclined plane is
Zero
Maximum
Minimum
None of these
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 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
One Newton is equivalent to
1 kg. wt
9.81 kg. wt
981 dyne
1/9.81 kg. wt
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
The Centre of gravity of a 10 × 15 × 5 cm T-section from its bottom, is
7.5 cm
5.0 cm
8.75 cm
7.85 cm
Newton's law of Collision of elastic bodies states that when two moving bodies collide each other, their velocity of separation
Is directly proportional to their velocity of approach
Is inversely proportional to their velocity of approach
Bears a constant ratio to their velocity of approach
Is equal to the sum of their velocities of approach
A retarding force on a body does not
Change the motion of the body
Retard the motion of the body
Introduce the motion of the body
None of these