PHISICS(Rotational Motion)

1. The moment of inertia of a uniform rod of mass 0.5kg and length of 1m is 0.1kg/m2.about an
axis perpendicular to the rod. Find the distance of this line from the middle point of the rod.
2. A body rotating at 20 rad/s is acted upon by a constant torque providing it a deceleration of
2 rad/s2.At what time will the body have kinetic energy same as the initial value if the torque
continues to act?
3. A square plate of mass 120 g and edge 5 cm rotates about one of the edges. If it has a
uniform angular acceleration of 0.2 rad/s2,What torque acts on the plate?
4. A wheel is making revolutions about its axis with uniform angular acceleration. Starting from
rest, it reaches 100 rev/sec in 4 sec.Find the angular acceleration. Find the angle rotated
during those four seconds.
5. A Wheel rotating with uniform angular acceleration covers 50 revolutions in the first 5
seconds after the start. Find the angular acceleration and the angular velocity at the end of
five seconds.
6. AIEEE(2007)
Angular momentum of the particle rotating with a central force is constant due to
(1) Constant Force
(2) Constant linear momentum.
(3) Zero Torque
(4) Constant Torque
7.The mass of a space ship is 1000 kg .It is to be launched from the earth’s surface out in to
free space .The value of g and radius of the earth are 10 m/s2and 6400 km .Find the required
energy for this work. AIEEE 2012
A ball of mass (m) 0.5 kg is attached to the end of a string having length
(L) 0.5 m. The ball is rotated on a horizontal circular path about vertical
axis. The maximum tension that the string can bear is 324 N. Find the
maximum possible value of angular velocity of ball (in radian/s)
9.A 100 kg race car moves around a flat circular track of radius 50 m with a constant speed. The car
makes one revolution around the track every 10 seconds. Find the speed of the car ,the
acceleration of the car ,the frictional force between the tyres and the road provides the centripetal
10.Two children sit on seesaw that is 9m long and pivots on an axis at its center.The first child has a
mass m1 of 20 kg and sits at the left end of the seesaw ,while the second child has a mass m2 of 40
kg and sits somewhere on the seesaw to the right of the axis .At what distance r2 from the axis
should the second child sit to keep the horizontal? SAT -PHYSICS