The angular momentum of a rotating body changes from Ao to 4Ao in 4 minutes. The torque acting on the body is:
3/4 Ao
4Ao
3Ao
3/2Ao
If a spherical ball rolls on a table without slipping the friction of its total energy associated with rotational energy is :
3/5
2/7
2/5
3/7
The equation of stationary wave along a stretched string is given by where, x and y are in cm and t in second. The separation between two adjacent nodes is :
1.5 cm
3 cm
6 cm
4 cm
If the angle between the vectors , the value of the product is equal to
BA2 sinθ
BA2 sinθ cosθ
zero
The moment of inertia of a uniform circular disc of radius R and mass M about an axis passing from the edge of the disc and normal to the disc is
MR2
D.
We should use parallel axis theorem.
Moment of inertia of disc passing through its centre of gravity and perpendicular to its plane
Using theorem of parallel axes, we have
The role of moment of inertia in the study of rotational motion is analogous to that of mass in study of linear motion.
A force of acts on O, the origin of the coordinate systems. The torque about the point (1, -1 ) is
The speed of earth's rotation about its axis is o. Its speed is increased to x times to make the effective acceleration due to gravity equal to zero at the equator. Then x is
1
8.5
17
34
The moment of inertia of a uniform circular disc of radius R and mass M about an axis passing from the edge of the disc and normal to the disc is
MR2
Point masses 1, 2, 3 and 4 kg are lying at the points (0, 0, 0), (2, 0, 0), (0, 3, 0) and (- 2, -2, 0) respectively. The moment-of inertia of this system about X-axis will be
43 kg-m2
34 kg-m2
27 kg-m2
72 kg-m2
The radius of gyration of a body about an axis at a distance 6 cm from its centre of mass is 10 cm. Then, its radius of gyration about a parallel axis through its centre of mass will be
80 cm
8 cm
0.8 cm
80 m