EASY
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The rotor of a ship rotates in clockwise direction when viewed from the stern and the ship takes a left turn. The effect of the gyroscopic couple acting on it will be 

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Important Questions on Motion of System of Particles and Rigid Bodies

EASY

A solid disc of radius a and mass m rolls down without slipping on an inclined plane making an angle θ with the horizontal. The acceleration of the disc will be 2 bgsinθ, where b is _______.  (Round off to the nearest integer)

(g= acceleration due to gravity and θ= angle as shown in figure)

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MEDIUM
A uniform solid sphere of radius R and radius of gyration K about an axis passing through the centre of mass, is rolling without slipping. Then the fraction of total energy associated with its rotation will be
MEDIUM
A ball is spun with angular acceleration α=6t2-2t where t is in second and α is in rad s-2. At t=0, the ball has angular velocity of 10 rad s-1 and angular position of 4 rad. The most appropriate expression for the angular position of the ball is
EASY

The angular speed of truck wheel is increased from 900 rpm to 2460 rpm in 26 seconds. The number of revolutions by the truck engine during this time is ______.

(Assuming the acceleration to be uniform).

EASY
A particle of mass 10 g moves along a circle of radius 6.4 cm with a constant tangential acceleration. What is the magnitude of this acceleration if the kinetic energy of the particle becomes equal to 8×10-4 J by the end of the second revolution after the beginning of the motion?
MEDIUM

A ball is rolling without slipping in a spherical shallow bowl (radius R ) as shown in the figure and is executing simple harmonic motion. If the radius of the ball is doubled, then the time period of oscillation

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HARD
A cylinder of mass, m is allowed to roll on a smooth horizontal table with a spring of spring constant, k attached to it so that it executes SHM about the equilibrium position. What is the time period, T of oscillations?
MEDIUM
Consider two uniform discs of the same thickness and different radii  R1=R and R2=αR made of the same material. If the ratio of their moments of inertia I1 and I2, respectively, about their axes is I1:I2=1:16 then the value of α is :
MEDIUM

One end of a rod of length L=1 m is fixed to a point on the circumference of a wheel of radius R=13 m. The other end is sliding freely along a straight channel passing through the center O of the wheel as shown in the figure below. The wheel is rotating with a constant angular velocity ω (in radian per second) about O.

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The speed of the sliding end P when θ=60° is

MEDIUM
A uniform ring of radius R is moving on a horizontal surface with speed v, then climbs up a ramp of inclination 30° to a height h. There is no slipping in the entire motion. Then, h is
MEDIUM

A wheel of radius "rolls without slipping with a speed v on a horizontal road. When it is at a point A on the road a small bob of the mud separates from wheel at the highest point and touches the point B on the road as shown in the figure. Then AB is (g-acceleration due to gravity)

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MEDIUM

A rigid massless rod of length 3l has two masses attached at each end as shown in the figure. The rod is pivoted at point P on the horizontal axis. When released from the initial horizontal position, its instantaneous angular acceleration will be


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HARD
A body of mass m slides down an incline and reaches the bottom with a velocity. v. If the same mass were in the form of a ring which rolls down this incline. The velocity of the ring at the bottom would have been
MEDIUM
A rigid body is in pure rotation, that is undergoing fixed axis rotation. Then which of the following statements are true -
MEDIUM

A sphere, a ring and a disc of same mass and radius are allowed to roll down three similar sufficiently rough inclined planes as shown in the figure from same height.
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Which of the following order is true for final KE of the bodies?

MEDIUM

A particle of mass m moving horizontally with a velocity v0 collides and sticks to the bottom of the smoothly pivoted hanging rod of mass M (= 3 m) and length l.

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The maximum height raised by the CM of the rod
HARD
A cord is wrapped on a pulley (disk) of mass M and radius R as shown in Figure. To one end of the cord, a block of mass M is connected as shown and to other end in (a) a force of 2 Mg and in (b) a block of mass 2M. Let angular acceleration of the disk in A and B is αA and αB respectively, then (cord is not slipping on the pulley)


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EASY
A solid sphere, a hollow sphere and a ring are released from top of an inclined plane (frictionless) so that they slide down(no rolling) the plane. Then maximum acceleration down the plane is for
HARD

A solid sphere is set into rotation at an angular velocity ω0 and it is then, placed on a rough horizontal surface. The ratio of distances covered by rotational and translational motions up to the start of the pure rolling is (assume uniformly accelerated motion up to start of pure rolling):

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HARD

A cylinder moves with linear velocity v to the right and angular velocity ω in the anticlockwise direction. The cylinder was initially at rest. The cylinder does not perform pure rolling and stops after some time. What will be the radius of the cylinder?

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