A flywheel rotating about a fixed axis has a kinetic energy of 360J when its angular speed is 30 rad/s. The moment of inertia of the wheel about the axis of rotation is _______.
0.6 kgm2
0.15 kgm2
0.8 kgm2
0.75 kgm2
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 diameter of the ring. They will now rotate with an angular velocity.
O is the centre of an equilateral triangle ABC. F1, F2 and F3 are three forces acting along the side AB, BC and AC as shown in figure. What should be the magnitude of F3. So that the total torque about O is zero ?
( F1 + F2 ) /2
( F1 - F2 )
(F1 + F2 )
2 (F1 + F2 )
A thin circular ring of mass M and radius r is rotating about its axis with a constant angular velocity ω. Four objects each of mass m, are kept gently to the opposite ends of two perpendicular diameters of the ring. The angular velocity of the ring will be
A solid sphere, disc and solid cylinder, all of the same mass and made of same material are allowed to roll down ( from rest ) on the inclined plane, then :
Solid sphere reaches the bottom first
Solid sphere reaches the bottom last
Disc will reach the bottom first
All reach the bottom at the same time
A circular disc is to be made using iron and aluminium. To keep its moment of inertia maximum about a geometrical axis, it should be so prepared that
Aluminium is at the interior and iron surrounds it.
Iron is at the interior and aluminium surrounds it.
Aluminium and iron layers are in alternate order.
Sheet of iron is used at both external surfaces and aluminium sheet as inner material.
If a sphere is rolling, the ratio of the translational energy to total kinetic energy is given by _____.
7 : 10
2 : 5
10 : 7
5 : 7
Angular momentum :
Vector (axial )
Vector ( polar )
Scalar
None of these
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 fraction of total energy associated with its rotational energy will be
The amount of inertia of uniform circular disc of radius r and mass M about an axis passing from the edge of the disc and normal to the disc
1/2 MR2
MR2
7/2 MR2
3/2 MR2