### Eamcet - Physics - Rotatory Motion

Identify the increasing order of the angular velocities of the following :1.earth rotating about its own axis2.hour's hand of a clock3.second's hand of a clock4.flywheel of radius 2 m making 300 rpm

A.  1,2,3,4

B.  2,3,4,1

C.  3,4,1,2

D.  4,1,2,3

Two particles P and Q are located at distance rp and rq respectively from the centre of a rotating disc such that rp > rq

A.  Both P and Q have the same acceleration

B.  Both P and Q do not have any acceleration

C.  P has greater acceleration than Q

D.  Q has greater acceleration than P

Two solid spheres (A and B) are made of metals of different densities and ρA  and ρB  respectively. If their masses are equal, the ratio of their moments of inertia {IB/IA) about their respective diameter is

A.  (ρB /ρA )2/3

B.  (ρA /ρB )2/3

C.  (ρA /ρB )

D.  (ρB /ρA )

A uniform rod of length 8a and mass 6m lies on a smooth horizontal surface. Two point masses m and 2m moving in the same plane with speed 2 v and v repectively strike the rod perpendicularly at distances a and 2a from the mid point of the rod in the opposite directions and stick to the rod. The angular velocity of the system immediately after the collision is:

A.  6v/32a

B.  6v/33a

C.  6v/40a

D.  6v/41a

A thin metal disc of radius 0.25 m and mass 2 kg starts from rest and rolls down an Inclined plane. If its rotational kinetic energy is 4 J at the foot of the inclined plane, then its linear velocity at the same point is:

A.  1.2 m/s

B.  2√2 m/s

C.  20 m/s

D.  2 m/s

A wheel has a speed of 1200 revolution per minute and is made to slow down at a rate of 4 radian/sec2. The number of revolutions it makes before coming to rest is :

A.  143

B.  272

C.  314

D.  722