Two Circular discs A and B are of equal masses and thicknesses but made of metal with densities dA and dB (dA > dB). If their moments of inertia about an axis passing through their centers and perpendicular to circular faces be IA and IB, then
1. IA = IB
2. IA > IB
3. IA < IB
4. IA ≥ IB
A body is rolling without slipping on a horizontal surface and its rotational kinetic energy is equal to the translational kinetic energy. The body is
1. Disc
2. Sphere
3. Cylinder
4. Ring
A wheel with a radius of 20 cm has forces applied to it as shown in the figure. The torque produced by the forces of 4 N at A, 8 N at B, 6 N at C, and 9 N at D, at the angles indicated, is:
1. 5.4 N-m anticlockwise
2. 1.80 N-m clockwise
3. 2.0 N-m clockwise
4. 3.6 N-m clockwise
The moment of inertia of a thin rectangular plate ABCD of uniform thickness about an axis passing through the centre O and perpendicular to the plane of the plate is
1. I1+I2
2. I2+I4
3. I1−I3
4. I1+I2+I3+I4
The centre of a wheel rolling on a plane surface moves with a speed v0. A particle on the rim of the wheel at the same level as the centre will be moving at speed:
1. zero
2. v0
3. √2v0
4. 2v0
Moment of inertia of a uniform cylinder of mass M, radius R and length l about an axis passing through its center and normal to its axis would be
1. Ml212
2. MR22
3. M[l212 + R24]
4. M[l212 + R22]
A particle moves along a circle of radius 20πm with constant tangential acceleration. If the velocity of the particle is 80 m/s at the end of the second revolution after motion has begin, the tangential acceleration is
1. 640 π m/s2
2. 160 π m/s2
3. 40 π m/s2
4. 40 m/s2
If the radius of the earth is suddenly contracted to half of its present value, then the duration of the day will be of:
1. | 6 hours | 2. | 12 hours |
3. | 18 hours | 4. | 24 hours |
A wheel has angular acceleration of 3.0 rad/sec2 and an initial angular speed of 2.00 rad/sec. In a time of 2 sec it has rotated through an angle (in radian) of
1. 10
2. 12
3. 4
4. 6
If a force acts on a body at a point away from the centre of mass, then
1. Linear acceleration changes
2. Angular acceleration changes
3. Both change
4. None of these