JEE Questions for Physics Systems Of Particles And Rotational Motion Quiz 14 - MCQExams.com

What remains constant when the earth revolves around the sun ?
  • Linear kinetic energy
  • Angular momentum
  • Linear momentum
  • Angular kinetic energy
A circular turn table has a block of ice placed at its centre.The system rotates with an angular speed ω about an axis passing through the centre of the table. If the ice melts on its own without any evaporation, the speed of rotation of the system
  • Becomes zero
  • Remains constant at the same value ω
  • Increases to a value greater than ω
  • Decreases to a value less than ω
When a man stands on a turn-table stretching with two equal loads in hand and rotates. Then he folds his arm. Which of the following statement is correct?
  • Linear momentum in conserved
  • Kinetic energy increases
  • Angular momentum increases
  • Angular velocity increases
  • Both (and (4)
A homogeneous disc of mass 2 kg and radius 15 cm is rotating about its axis (which is fixed) with an angular velocity of 4 rad/s. The linear momentum of the disc is
  • 1.2 kg-m/s
  • 1.0 kg-m/s
  • 0.6 kg-m/s
  • None of these
Angular momentum of a body is defined as the product of
  • Mass and angular velocity
  • Centripetal force and radius
  • Linear velocity and angular velocity
  • Moment of inertia and angular velocity
A boy comes running and sits on a rotating platform. What is conserved ?
  • Linear momentum
  • Kinetic energy
  • Angular momentum
  • None of these
A man turns on a rotating table with an angular speed ω. He is holding two equal masses at arm\'s length. Without moving his arms, he just drops the two masses. How will his angular speed change?
  • It will be less than ω
  • It will be more than ω
  • It will remain equal to ω
  • May be less than, greater than or equal to ω depending on the quantity of masses
A small object of mass m is attached to a light string which passes through a hollow tube. The tube is hold by one hand and the string by the other. The object is set into rotation in a circle of radius R and velocity v. The string is then pulled down, shortening the radius of path of r. What is conserved ?
  • Angular momentum
  • Linear momentum
  • Kinetic energy
  • None of these
A ring of mass 10 kg and diameter 0.4 m is rotated about its axis. If it makes 2100 revolution per minute, then its angular momentum will be
  • 44 kg × m2/s
  • 88 kg × m2/s
  • 4.4 kg × m2/s
  • 0.4 kg × m2/s
A round disc of moment of inertia I2 about its axis perpendicular to its plane and passing through its centre is placed over another disc of moment of inertia I1 rotating with an angular velocity ω about the same axis. The final angular velocity of the combination of discs is

  • Physics-Systems of Particles and Rotational Motion-90100.png
  • ω

  • Physics-Systems of Particles and Rotational Motion-90101.png

  • Physics-Systems of Particles and Rotational Motion-90102.png
A diver in a swimming pool bends his head before diving, because it
  • Decreases his moment of inertia
  • Decreases his angular velocity
  • Increases his moment of inertia
  • Increases his linear velocity
The angular momentum of a system of particles is not conserved
  • When a net external force acts upon the system
  • When a net external torque is acting upon the system
  • When a net external impulse in acting upon the system
  • None of the above
A man is standing at the edge of a circular plate which is rotating with a constant angular speed about a perpendicular axis passing through the centre. If the man walks towards the axis along the radius, its angular velocity
  • Decreases
  • Remains constant
  • Increases
  • Information is incomplete
A particle of mass m moves in the XY plane with a velocity V along the straight line AB. If the angular momentum of the particle with respect to origin O is LA when it is at A and LB when it is at B, then
Physics-Systems of Particles and Rotational Motion-90104.png
  • LA > LB
  • LA = LB
  • The relationship between LA and LB depends upon the slope of the line AB
  • LA < LB
In the absence of external torque for a body revolving about any axis, the quantity that remains constant is
  • Kinetic energy
  • Potential energy
  • Linear momentum
  • Angular momentum
  • Linear velocity
When a mass is rotating in a plane about a fixed point, its angular momentum is directed along
  • A line perpendicular to the plane of rotation
  • The line making an angle of 45° to the plane of rotation
  • The radius
  • The tangent to the orbit
According to the theorem of parallel axes I = Icm + Mx2, the graph between I and x will be

  • Physics-Systems of Particles and Rotational Motion-90106.png
  • 2)
    Physics-Systems of Particles and Rotational Motion-90107.png

  • Physics-Systems of Particles and Rotational Motion-90108.png

  • Physics-Systems of Particles and Rotational Motion-90109.png
Which of the following statement regarding the angular speed about the instantaneous axis (passing through the centre of mass) is correct

  • Physics-Systems of Particles and Rotational Motion-90110.png
  • 2)
    Physics-Systems of Particles and Rotational Motion-90111.png

  • Physics-Systems of Particles and Rotational Motion-90112.png

  • Physics-Systems of Particles and Rotational Motion-90113.png
A ball rolls without slipping. The radius of gyration of the ball about an axis passing through its centre of mass is K. If radius of the ball be R, then the friction of total energy associated with its rotational energy will be

  • Physics-Systems of Particles and Rotational Motion-90114.png
  • 2)
    Physics-Systems of Particles and Rotational Motion-90115.png

  • Physics-Systems of Particles and Rotational Motion-90116.png

  • Physics-Systems of Particles and Rotational Motion-90117.png
A solid spherical ball rolls on an inclined plane without slipping.The ratio of rotational energy and total energy is

  • Physics-Systems of Particles and Rotational Motion-90119.png
  • 2)
    Physics-Systems of Particles and Rotational Motion-90120.png

  • Physics-Systems of Particles and Rotational Motion-90121.png

  • Physics-Systems of Particles and Rotational Motion-90122.png
The M.I. of a body abut the given axis is 1.2 kg × m2 initially the body is at rest. In order to produce a rotational kinetic energy of 1500 J, an angular acceleration of 25 rad/sec2 must be applied about that axis for duration of
  • 4 sec
  • 2 sec
  • 8 sec
  • 10 sec
The ratio of rotational and translatory kinetic energies of a sphere is

  • Physics-Systems of Particles and Rotational Motion-90124.png
  • 2)
    Physics-Systems of Particles and Rotational Motion-90125.png

  • Physics-Systems of Particles and Rotational Motion-90126.png

  • Physics-Systems of Particles and Rotational Motion-90127.png
When a sphere of moment of inertia I about its centre of gravity and mass \'m\' rolls from rest down an inclined plane without slipping, its kinetic energy is

  • Physics-Systems of Particles and Rotational Motion-90129.png
  • 2)
    Physics-Systems of Particles and Rotational Motion-90130.png

  • Physics-Systems of Particles and Rotational Motion-90131.png

  • Physics-Systems of Particles and Rotational Motion-90132.png
A thin hollow cylinder open at both ends
(i) Sliding without rolling
(ii) Rolls without slipping, with the same speed
The ratio of kinetic energy in the two cases is
  • 1 : 1
  • 4 : 1
  • 1 : 2
  • 2 : 1
If \'I\' is the moment of inertia of a body and \'ω\' is its angular velocity, then its rotational kinetic energy is

  • Physics-Systems of Particles and Rotational Motion-90134.png
  • 2)
    Physics-Systems of Particles and Rotational Motion-90135.png

  • Physics-Systems of Particles and Rotational Motion-90136.png

  • Physics-Systems of Particles and Rotational Motion-90137.png
A body is rolling without slipping on a horizontal surface and its rotational kinetic energy is equal to the translational kinetic energy. The body is
  • Disc
  • Sphere
  • Cylinder
  • Ring
The total kinetic energy of rolling solid sphere having translational velocity v is

  • Physics-Systems of Particles and Rotational Motion-90139.png
  • 2)
    Physics-Systems of Particles and Rotational Motion-90140.png

  • Physics-Systems of Particles and Rotational Motion-90141.png

  • Physics-Systems of Particles and Rotational Motion-90142.png
A body having moment of inertia about its axis of rotation equal to 3kg-m2 is rotating with angular velocity equal to 3 rad/s. Kinetic energy of this rotating body is the same as that of body of mass 27 kg moving with a speed of
  • 1.0 m/s
  • 0.5 m/s
  • 1.5 m/s
  • 2.0 m/s
A ring of radius r and mass m rotates about an axis passing through its centre and perpendicular to its plane with angular velocity ω. Its kinetic energy is
  • mrω2
  • mrω2/2
  • mr2ω2

  • Physics-Systems of Particles and Rotational Motion-90147.png
A hollow sphere of diameter 0.2 m and mass 2 kg is rolling on an inclined plane with velocity v = 0.5 m/s. The kinetic energy of the sphere is
  • 0.1 J
  • 0.3 J
  • 0.5 J
  • 0.42 J
A flywheel rotating about a fixed axis has a kinetic energy of 360 J when its angular speed is 30 rad/sec. The moment of inertia of the wheel about the axis of rotation is
  • 0.6 kg × m2
  • 0.15 kg × m2
  • 0.8 kg × m2
  • 0.75 kg × m2
Two rigid bodies A and B rotate with rotational kinetic energies EA and EB respectively. The moments of inertia of A and B about the axis of rotation are IA and IB respectively. If IA = IB / 4 and EA = 100 EB the ratio of angular momentum (LA) of A to the angular momentum (LB) of B is
  • 5/4
  • 25
  • 5
  • 1/4
A sphere rolls down on an inclined plane of inclination θ. What is the acceleration as the sphere reaches bottom ?

  • Physics-Systems of Particles and Rotational Motion-90154.png
  • 2)
    Physics-Systems of Particles and Rotational Motion-90155.png

  • Physics-Systems of Particles and Rotational Motion-90156.png

  • Physics-Systems of Particles and Rotational Motion-90157.png
A solid cylinder of mass M and radius R rolls without slipping down an inclined plane of length L and height h. What is the speed of its centre of mass when the cylinder reaches its bottom?

  • Physics-Systems of Particles and Rotational Motion-90159.png
  • 2)
    Physics-Systems of Particles and Rotational Motion-90160.png

  • Physics-Systems of Particles and Rotational Motion-90161.png

  • Physics-Systems of Particles and Rotational Motion-90162.png
A cord is wound round the circumference of wheel of radius. The axis of the wheel is horizontal and moment of inertia about it is I. A weight mg is attached to the end of the cord and falls from the rest. After falling through a distance h, the angular velocity of the wheel will be

  • Physics-Systems of Particles and Rotational Motion-90164.png
  • 2)
    Physics-Systems of Particles and Rotational Motion-90165.png

  • Physics-Systems of Particles and Rotational Motion-90166.png

  • Physics-Systems of Particles and Rotational Motion-90167.png
A solid cylinder 30 cm in diameter at the top of an inclined plane 2.0 m high is released and rolls down the incline without loss of energy due to friction.Its linear speed at the bottom is
  • 5.29 m/sec
  • 4.1 × 103 m/sec
  • 51 m/sec
  • 51 cm/sec
A ring solid sphere and a disc are rolling down from the top of the same height, then the sequence to reach on surface is
  • Ring, disc, sphere
  • Sphere, disc, ring
  • Disc, ring, sphere
  • Sphere, ring, disc
If a hollow cylinder and a solid cylinder are allowed to roll down in inclined plane, which will take more time to reach the bottom ?
  • Hollow cylinder
  • Solid cylinder
  • Same for both
  • One whose density is more
A solid cylinder rolls down an inclined plane of height 3 m and reaches the bottom of plane with angular velocity of 2√2 rad.s–1. The radius of cylinder must be [Take g = 10 ms–2]
  • 5 cm
  • 0.5 cm
  • √10 cm
  • √5 cm

Physics-Systems of Particles and Rotational Motion-90172.png
  • Ring
  • Solid sphere
  • Hollow sphere
  • Disc
A circular disc of radius R and thickness R/6 has moment of inertia I about an axis passing through its centre and perpendicular to its plane. It is melted and recasted into a solid sphere. The momentum of inertia of the sphere about its diameter as axis of rotation is
  • I
  • 2I/8
  • I/5
  • I/10
Let I be the moment of inertia of a uniform square plate about an axis AB that passes through its centre and is parallel to two of its sides. CD is a line in the plane of the plate that passes through the centre of the plate and makes an angle θ with AB. The moment of inertia of the plate about the axis CD is then equal to
  • I
  • I sin2 θ
  • I cos2 θ

  • Physics-Systems of Particles and Rotational Motion-90175.png
A thin circular ring of mass M and radius r is rotating about its axis with a constant angular velocity ω. Two objects each of mass m are attached gently to the opposite ends of a diameter of the ring. The ring will now rotate with an angular velocity

  • Physics-Systems of Particles and Rotational Motion-90177.png
  • 2)
    Physics-Systems of Particles and Rotational Motion-90178.png

  • Physics-Systems of Particles and Rotational Motion-90179.png

  • Physics-Systems of Particles and Rotational Motion-90180.png
A straight rod of length L has one of its ends at the origin and the other at x = L. If the mass per unit length of the rod is given by Ax where A is constant, where is its mass centre?
  • L/3
  • L/2
  • 2L/3
  • 3L/4
A smooth sphere A is moving on a frictionless horizontal plane with angular speed ω and centre of mass velocity v. It collides elastically and head on with an identical sphere B at rest. Neglect friction everywhere. After the collision, their angular speeds are ωA and ωB respectively.Then
  • ωA < ωB
  • ωA = ωB
  • ωA = ω
  • ω = ωB
A rigid body of mass m rotates with the angular velocity w about an axis at a distance \'a\' from the centre of mass G. The radius of gyration about G is K. Then kinetic energy of rotation of the body about new parallel axis is

  • Physics-Systems of Particles and Rotational Motion-90190.png
  • 2)
    Physics-Systems of Particles and Rotational Motion-90191.png

  • Physics-Systems of Particles and Rotational Motion-90192.png

  • Physics-Systems of Particles and Rotational Motion-90193.png
A uniform cylinder has a radius R and length L. If the moment of inertia of this cylinder about an axis passing through its centre and normal to its circular face is equal to the moment of inertia of the same cylinder about an axis passing through its centre and perpendicular to its length, then
  • L = R
  • 2)
    Physics-Systems of Particles and Rotational Motion-90195.png

  • Physics-Systems of Particles and Rotational Motion-90196.png

  • Physics-Systems of Particles and Rotational Motion-90197.png
The rectangular block shown in the figure is rotated in turn about x - x, y - y and z - z axis passing through its centre of mass 0. Its moment of inertia is
Physics-Systems of Particles and Rotational Motion-90199.png
  • Same about all the three axis
  • Maximum about z - z axis
  • Equal about x - x and y - y axis
  • Maximum about y - y axis
A wheel of moment of inertia 5 × 10–3 kg–m2 is making 20 revolutions/sec. The torque required to stop it in 10 sec is
  • 2π × 10–2 N-m
  • 2π × 102 N-m
  • 4π × 10–2 N-m
  • 4π × 102 N-m
2 bodies of different masses of 2 kg and 4 kg are moving with velocities 20 m/s and 10 m/s towards each other due to mutual gravitational attraction. What is the velocity of their centre of mass?
  • 5 m/s
  • 6 m/s
  • 8 m/s
  • Zero
0:0:1


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