A ring of mass m and radius r rotates about an axis passing through its centre and perpendicular to its plane with an angular velocity ω. Its kinetic energy is
1/2 mr2 ω2
mr ω2
mr2 ω2
1/2 mr ω2
A particle of mass m = 5kg is moving with a uniform speed v = 3√2 in the XOY plane along the line Y = X + 4. The magnitude of the angular momentum of the particle about the origin is
60 unit
40 √2 unit
zero
7.5 unit
The dimensional representation of moment of inertia is
[ML 2T0]
[ML -2T0]
[ML 2T-2]
[ML 0T0]
SI unit of moment of inertia is
kg
kg m2
kg m-2
None of these
The moment of inertia of a straight thin rod of mass M and length L about an axis perpendicular to its length and passing through its end is
ML2
A man is sitting on a rotating table with his arms stretched outwards. When he suddenly folds his arms, his
angular velocity decreases
moment of inertia decreases
angular velocity remains constant
angular momentum increases
When a torque acting upon a system is zero which of the following will be a constant?
Force
Linear momentum
Angular momentum
The moment of inertia of a body about a given axis is 1.2kg-m2. Initially, the body is at rest. In order to produce a rotational kinetic energy of 1500J, an angular acceleration of 25 rad/s2 must be applied about that axis for a duration of
4 s
2 s
8 s
10 s
A constant torque acting on a uniform circular wheel changes its angular momentum from A to 4A in 4 seconds. The magnitude of this torque is
A
4 A
12 A
Two bodies with moment of intertia I1 and I2 (I1> I2) have equal angular momentum. If the K.E. of rotation are E1 and E2, then
E1 = E2
E1 > E2
E1 < E2
E1 ≥ E2
