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
Correct Answer :
D. All the above
Related Questions
In case of S.H.M. the period of oscillation (T), is given by
T = 2ω/π²
T = 2π/ω
T = 2/ω
T = π/2ω
Time required to stop a car moving with a velocity 20 m/sec within a distance of 40 m, is
2 sec
3 sec
4 sec
5 sec
If two bodies of masses M1 and M2(M1 > M2) are connected by alight inextensible string passing over a smooth pulley, the tension in the string, will be given by
T = g(M1 - M2)/(M1 + M2)
T = g(M1 + M2)/(M1 × M2)
T = g(M2 - M1)/(M1 + M2)
T = g(M2 + M1)/(M2 - M1)
Rate of change of angular momentum is equal to
Force
Torque
Linear momentum
Impulse
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
The resultant of two forces acting at right angles is √34 kg and acting at 60° is 70 kg. The forces are
1 kg and 4 kg
2 kg and 3 kg
√3 kg and √5 kg
3 kg and 5 kg
The Law of Polygon of Forces states that
If a polygon representing the forces acting at point in a body is closed, the forces are in equilibrium
If forces acting on a point can be represented in magnitude and direction by the sides of a polygon taken in order, then the resultant of the forces will be represented in magnitude and direction by the closing side of the polygon
If forces acting on a point can be represented of a polygon taken in order, their sides of a polygon taken in order, their resultant will be represented in magnitude and direction by the closing side of the polygon, taken in opposite order
If forces acting on a point can be represented in magnitude and direction by the sides of a polygon in order, the forces are in equilibrium
If a ball which is dropped from a height of 2.25 m on a smooth floor attains the height of bounce equal to 1.00 m, the coefficient of the restitution between the ball and floor, is
0.25
0.50
0.67
0.33
Newtons Law of Motion is:
Everybody continues in its state of rest or of uniform motion in a straight line, unless it is acted upon by some external force
The rate of change of momentum is directly proportional to the impressed force, and takes place in the same direction, in which the force acts
To every action, there is always an equal and opposite reaction
All the above
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
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 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
The intrinsic equation of catenary is
S = c tan ψ
y = c cosh x/c
y = c cosh ψ
y = c sinh ψ
The acceleration of a train starting from rest at any instant is 1/6(V + 1) m/sec² where V is the velocity of the train in m/sec. The train will attain a velocity of 36 km/hour after travelling a distance of
2000 m
2100 m
2200 m
2300 m
The equation of motion of a particle starting from rest along a straight line is x = t3 - 3t2+ 5. The ratio of the accelerations after 5 sec and 3 sec will be
2
3
4
5
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
Which one of the following statements is true?
The tangent of the angle of friction is equal to coefficient of friction
The angle of repose is equal to angle of friction
The tangent of the angle of repose is equal to coefficient of friction
All the above
A flywheel of moment of inertia 20 kgm is acted upon by a tangential force of 5 N at 2 m from its axis, for 3 seconds. The increase in angular velocity in radian per second is
1/2
3/2
2
3
A load of 500 kg was lifted through a distance of 13 cm. by an effort of 25 kg which moved through a distance of 650 cm. The mechanical advantage of the lifting machine is
15
18
20
26
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
A 49 kg lady stands on a spring scale in an elevator. During the first 5 sec, starting from rest, the scale reads 69 kg. The velocity of the elevator will be
10 m/sec
15 m/sec
20 m/sec
25 m/sec
A ball moving with a velocity of 5 m/sec impinges a fixed plane at an angle of 45° and its direction after impact is equally inclined to the line of impact. If the coefficient of restitution is 0.5, the velocity of the ball after impact will be
0.5 m/sec
1.5 m/sec
2.5 m/sec
3.5 m/sec
Effect of a force on a body depends upon its
Direction
Magnitude
Position
All the above
The resultant of two forces P and Q is R. If Q is doubled, the new resultant is perpendicular to P. Then,
P = R
Q = R
P = Q
None of the above is correct
Time period and length of a seconds pendulum respectively are
1 sec and 99.4 cm
1 sec and 92.7 cm
2 sec and 99.4 cm
2 sec and 92.7 cm
The units of moment of inertia of an area are
kg/m
kg/m2
m4
m3
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
For lifting a load of 50 kg through a distance of 2.5 cm, an effort of 12.5 kg is moved through a distance of 40 cm. The efficiency of the lifting machine, is
60 %
65 %
70 %
75 %
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 practical units of work, is
Erg
Joule
Newton
Dyne