JEE Questions for Physics Systems Of Particles And Rotational Motion Quiz 1 - MCQExams.com

If the external torque acting on a system τ = 0, then
  • ω = 0
  • α = 0
  • J = 0
  • F = 0
Angular momentum of the particle rotating with a central force is constant due to
  • Constant forces
  • Constant linear momentum
  • Zero torque
  • Constant torque
The centre of mass of a body
  • lies always outside the body
  • may lie within, outside or on the surface of the body
  • lies always inside of the body
  • lies always on the surface of the body
The centre of mass of three particles of masses 1 kg, 2 kg and 3 kg is at (3, 3,with reference to a fixed coordinate system. Where should a fourth particle of mass 4 kg be placed, so that the centre of mass of the system of all particles shifts to a point (1, 1,?
  • (–1, –1, –1)
  • (–2, –2, –2)
  • (2, 2, 2)
  • (1, 1, 1)
A system consists of 3 particles each of mass m located at points (1, 1), (2,and (3, 3). The coordinates of the centre of mass are
  • (6, 6)
  • (3, 3)
  • (1, 1)
  • (2, 2)
  • (5, 5)

Physics-Systems of Particles and Rotational Motion-88552.png
  • (2, –5, 3)
  • (5, –5, -3)
  • (5, –4, –2)
  • (5, –4, –4)
Two particles A and B initially at rest, move towards each other, under mutual force of attraction. At an instance when the speed of A is v and speed of B is 2v, the speed of centre of mass is
  • zero
  • v
  • 2.5v
  • 4v
Two point objects of mass 1.5 g and 2.5 g respectively are at a distance of 16 cm apart, the centre of gravity is at a distance x from the object of mass 1.5 g, where x is
  • 10 cm
  • 6 cm
  • 13 cm
  • 3 cm
Identify the correct statement for the rotational motion of a rigid body.
  • Individual particles of the body do not undergo accelerated motion.
  • The centre of mass of the body remains unchanged.
  • The centre of mass of the body moves uniformly in a circular path.
  • Individual particles and centre of mass the body undergo an accelerated motion.
Two point masses of 0.3 kg and 0.7 kg are fixed at the ends of a rod of length 1.4 m and of negligible mass. The rod is set rotating about an axis perpendicular to its length with a uniform angular speed. The point on the rod through which the axis should pass in order that the work required for rotation of the rod is minimum, is located at a distance of
  • 0.42 m from mass of 0.3 kg
  • 0.70 m from mass of 0.7 kg
  • 0.98 m from mass of 0.3 kg
  • 0.98 m from mass of 0.7 kg
Statement I If there is no external torque on a body about its centre of mass, then the velocity of the centre of mass remains constant.
Statement II The linear momentum of an isolated system remains constant.
  • Statement I is true, Statement II is true, Statement II is a correct explanation for Statement I.
  • Statement I is true, Statement II is true, Statement II is not a correct explanation for Statement I.
  • Statement I is true, Statement II is false.
  • Statement I is false, Statement II is true.

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    Physics-Systems of Particles and Rotational Motion-88558.png

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The motion of the centre of mass is the result of
  • internal forces
  • external forces
  • attractive forces
  • repulsive forces
Consider a two particle system with particles having masses m1 and m2. If the first particles is pushed towards the centre of mass through a distance d, by what distance should the second particle be moved, so as to keep the centre of mass at the same position?

  • Physics-Systems of Particles and Rotational Motion-88562.png
  • 2)
    Physics-Systems of Particles and Rotational Motion-88563.png

  • Physics-Systems of Particles and Rotational Motion-88564.png

  • Physics-Systems of Particles and Rotational Motion-88565.png
The distance between the centres of carbon and oxygen atoms in the carbon monoxide molecule is 1.130A° . Locate the centre of mass of the molecule relative to the carbon atom
  • 5.428 Å
  • 1.130 Å
  • 0.6457 Å
  • 0.3260 Å
  • None of these
A small disc of radius 2 cm is cut from a disc of radius 6 cm. If the distance between their centres is 3.2 cm, what is the shift in the centre of mass of the disc?
  • 0.4 cm
  • 2.4 cm
  • 1.8 cm
  • 1.2 cm
If the external forces acting on a system have zero resultant, then the centre of mass
  • may move but not accelerate
  • may accelerate
  • must not move
  • None of the above
Three identical spheres, each of mass 1 kg are kept as shown in the figure below, touching each other, with their centres on a straight line. If their centres are marked P, Q, R respectively, the distance of centre of mass of the system from P is
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    Physics-Systems of Particles and Rotational Motion-88571.png

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  • Physics-Systems of Particles and Rotational Motion-88573.png

  • Physics-Systems of Particles and Rotational Motion-88574.png
The centre of mass of three particles of masses 1 kg, 2 kg and 3 kg is at (2, 2, 2). The position of the fourth mass of 4 kg to be placed in the system as that the new centre of mass is at (0, 0,is
  • (–3, –3, –3)
  • (–3, 3, –3)
  • (2, 3, –3)
  • (2, –2, 3)
If linear density of a rod of length 3 m varies as λ=2+x, then the position of the centre of gravity of the rod is

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  • 2)
    Physics-Systems of Particles and Rotational Motion-88578.png

  • Physics-Systems of Particles and Rotational Motion-88579.png

  • Physics-Systems of Particles and Rotational Motion-88580.png
The distance of the centre of mass of the T – shaped plate from O is
Physics-Systems of Particles and Rotational Motion-88582.png
  • 7 m
  • 2.7 m
  • 4 m
  • 1 m
In the figure, a ladder of mass m is shown leaning against a wall. It is in static equilibrium making an angle θ with the horizontal floor. The coefficient of friction between the wall and the ladder is μ1 and that between the floor and the ladder is μ2. The normal reaction of the wall on the ladder is N1 and that of the floor is N2. If the ladder is about to slip, then
Physics-Systems of Particles and Rotational Motion-88584.png
  • 90°
    Physics-Systems of Particles and Rotational Motion-88585.png
  • 120°
    Physics-Systems of Particles and Rotational Motion-88586.png
  • 30°
    Physics-Systems of Particles and Rotational Motion-88587.png
  • 45°
    Physics-Systems of Particles and Rotational Motion-88588.png
A uniform circular disc of mass 50 kg and radius 0.4 m is rotating with an angular velocity of 10 rad/s about its own axis, which is vertical. Two uniform circular rings, each of mass 6.25 kg and radius 0.2 m, are gently placed symmetrically on the disc in such a manner that they are touching each other along the axis of the disc and are horizontal. Assume that the friction is large enough such that the rings are at rest relative to the disc and the system rotates about the original axis. The new angular velocity (in rad/s-1) of the system is
  • 8
  • 7
  • 9
  • 11
A solid cylinder rolls from an inclined plane of height h. The velocity of body at bottom is

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    Physics-Systems of Particles and Rotational Motion-88592.png

  • Physics-Systems of Particles and Rotational Motion-88593.png

  • Physics-Systems of Particles and Rotational Motion-88594.png
A wire is wound on a hollow cylinder of radius 40 cm. Mass of the cylinder is 3 kg. Force of 30 N is applied on wire. The angular acceleration is
  • 25 rad / s2
  • 30 rad / s2
  • 35 rad / s2
  • 40 rad / s2
A wheel rotates with a constant angular velocity of 300 rpm. The angle through which the wheel rotates in 1 s is
  • π rad
  • 5π rad
  • 10π rad
  • 20π rad
When a disc is rotating with angular velocity ω, a particle situated at a distance of 4 cm just begins to slip. If the angular velocity is doubled, at what distance will the particle start to slip?
  • 1 cm
  • 2 cm
  • 3 cm
  • 4 cm
The ratio of angular speeds of minute hand and hour hand of a watch is
  • 1 : 12
  • 6 : 1
  • 12 : 1
  • 1 : 6
The angular velocity of a wheel increases from 100 to 300 in 10 s. The number of revolutions made during that time is
  • 600
  • 1500
  • 1000
  • 3000
  • 2000

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    Physics-Systems of Particles and Rotational Motion-88603.png

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  • Physics-Systems of Particles and Rotational Motion-88605.png
A motor is rotating at a constant angular velocity of 600 rpm. The angular displacement per second is

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    Physics-Systems of Particles and Rotational Motion-88608.png

  • Physics-Systems of Particles and Rotational Motion-88609.png

  • Physics-Systems of Particles and Rotational Motion-88610.png
The angle turned by a body undergoing circular motion depends on time as θ= θ0 + θ1t + θ2t2. Then, the angular acceleration of the body is
  • θ1
  • θ2
  • 2θ1
  • 2θ2
The instantaneous velocity of a point B of the given rod of length 0.5 m is 3ms -1 in the represented direction. The angular velocity of the rod for minimum velocity of end A is
Physics-Systems of Particles and Rotational Motion-88613.png
  • 1.5 rad s-1
  • 5.2 rad s-1
  • 2.5 rad s-1
  • None of these
Identify the increasing order of the angular velocities of the following :
I. Earth rotating about its own axis
II. Hour's hand of a clock
III. Second's hand of a clock
IV. Flywheel of radius 2 m making 300 rpm
  • I, II, III, IV
  • II, III, IV, I
  • III, IV, I, II
  • IV, I, II, III
A thin horizontal circular rotating about a vertical axis passing through its centre. An insect is at rest at a point near the rim of the disc. The insect now moves along a diameter of the disc to reach its other end. During the journey of the insect, the angular speed of the disc
  • continuously decreases
  • continuously increases
  • first increases and then decreases
  • remains unchanged

Physics-Systems of Particles and Rotational Motion-88617.png
  • The centre of mass of the assembly rotates about the z-axis with an angular speed of ω/5
  • The magnitude of angular momentum of center of mass of the assembly about the point O is 81 ma2ω
  • The magnitude of angular momentum of the assembly about its center of mass is 17 ma2ω/2.

  • Physics-Systems of Particles and Rotational Motion-88618.png
Moment of inertia of a disc about a diameter is I . Find the moment of inertia of disc about an axis perpendicular to its plane and passing through its rim?
  • 6 I
  • 4 I
  • 2 I
  • 8 I
From a circular ring of mass M and radius R, an arc corresponding to a 90° sector is removed. The moment of inertia of the remaining part of the ring about an axis passing through the centre of the ring and perpendicular to the plane of the ring is k times MR2 . Then the value of k is

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    Physics-Systems of Particles and Rotational Motion-88622.png

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  • Physics-Systems of Particles and Rotational Motion-88625.png
The moment of inertia of a circular ring of radius r and mass M about diameter is

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    Physics-Systems of Particles and Rotational Motion-88628.png

  • Physics-Systems of Particles and Rotational Motion-88629.png

  • Physics-Systems of Particles and Rotational Motion-88630.png
Moment of inertia of big drop is I. If 8 droplets are formed from big drop, then moment of inertia of small droplet is

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    Physics-Systems of Particles and Rotational Motion-88632.png

  • Physics-Systems of Particles and Rotational Motion-88633.png

  • Physics-Systems of Particles and Rotational Motion-88634.png
Moment of inertia of a ring of mass M and radius R about an axis passing through the centre and perpendicular to the plane is I. What is the moment of inertia about its diameter?

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  • 2)
    Physics-Systems of Particles and Rotational Motion-88637.png

  • Physics-Systems of Particles and Rotational Motion-88638.png

  • Physics-Systems of Particles and Rotational Motion-88639.png
Consider a uniform square plate of side a and mass m. The moment of inertia of this plate about an axis perpendicular to its plane and passing through one of its corners is
  • 5/6 ma2
  • 1/12 ma2
  • 7/12 ma2

  • Physics-Systems of Particles and Rotational Motion-88641.png
The moment of inertia of a thin circular disc about an axis passing through its centre and perpendicular to its plane is I. Then, the moment of inertia of the disc about an axis parallel to its diameter and touching the edge of the rim is
  • I
  • 2I

  • Physics-Systems of Particles and Rotational Motion-88643.png

  • Physics-Systems of Particles and Rotational Motion-88644.png
Two spheres of equal masses, one of which is a thin spherical shell and the other a solid, have the same moment of inertia about their respective diameters. The ratio of their radii will be
  • 5 : 7
  • 3 : 5
  • √3 : √5
  • √3 : √7
A thin wire of mass M and length L is bent to form a circular ring. The moment of inertia of this ring about its axis is

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  • 2)
    Physics-Systems of Particles and Rotational Motion-88648.png

  • Physics-Systems of Particles and Rotational Motion-88649.png

  • Physics-Systems of Particles and Rotational Motion-88650.png
A cubical block of side L rests on a rough horizontal surface with coefficient of friction m . A horizontal force F is applied on the block as shown. If the coefficient of friction is sufficiently high so that the block does not slide before toppling, the minimum force required to topple the block is
Physics-Systems of Particles and Rotational Motion-88652.png
  • infinitesimal
  • mg/4
  • mg/2
  • mg(1- m)
The moment of inertia of a circular ring of mass 1 kg about an axis passing through its centre and perpendicular to its plane is 4 kg–m2 . The diameter of the ring is
  • 2 m
  • 4 m
  • 5 m
  • 6 m
The moment of inertia about an axis of a body which is rotating with angular velocity 1 rad s -1 is numerically equal to
  • one–fourth of its rotational kinetic energy
  • half of the rotational kinetic energy
  • rotational kinetic energy
  • twice the rotational kinetic energy
The moment of inertia of a circular disc of radius 2 m and mass 2 kg, about an axis passing through its centre of mass is 2kg – m2. Its moment of inertia about an axis parallel to this axis and passing through its edge (in kg – m2) is
  • 10
  • 8
  • 6
  • 4
Moment of inertia of ring about its diameter is I. Then, moment of inertia about an axis passing through centre perpendicular to its plane is

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    Physics-Systems of Particles and Rotational Motion-88658.png

  • Physics-Systems of Particles and Rotational Motion-88659.png

  • Physics-Systems of Particles and Rotational Motion-88660.png
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