Home
Class 12
PHYSICS
A constant external torque tau acts for ...

A constant external torque `tau` acts for a very brief period `/_\t` on a rotating system having moment of inertia `I` then

A

The angular momentum of the system will change by `tau Deltat`

B

The angular velocity of the system will change by `(tauDeltat)/I`

C

If the system was initially at rest, it will acquire rotational kinetic energy `(tauDeltat)^(2)/(2I)`

D

The kinetic energy of the system will change by `(tauDeltat)^(2)/I`

Text Solution

Verified by Experts

The correct Answer is:
A, B, C
Let L= angular momentum
`tau = (dL)/(dt)` or `dL= tau dt`
For constant torque,
`DeltaL = tau Deltat = I Deltaomega` or `Iomega` if `omega_(i)=0`
Rotational kinetic energy `=1/2 Iomega^(2) = (DeltaL)^(2)/(2I)`
Promotional Banner

Similar Questions

Explore conceptually related problems

A constant external torque tau acts for a very brief period Delta t on a rotating system having moment of inertia I . ( i ) The angular momentum of the system will change by tau Delta t ( ii ) The angular velocity of the system will change by (tau Delta t)//I . ( iii ) If the system was initially at rest, it will acquire rotational kinetic energy (tau Delta t)^(2)//2I . ( iv ) The kinetic energy of the system will change by (tau Delta t)^(2) I .

Two particle are initially moving with angular momentum vec(L)_(1) and vec(L)_(2) in a region of space with no external torque. A constant external torque vec( tau) then acts on one particle, but not on the other particle, for a time interval Delta t . What is the chargne in the total angular momentum of the two particles ?

A toruque tau produces an angular acceleration in a body rotating about an axis of rotation. The moment of inertia of the body is increased by 50% by redistributing the masses, about the axis of rotation. To maintain the same angular acceleration, the torque is changed to tau' . What is the relation between tau and tau' ?

If net external torque, about a point, acting on the system is zero, then we can surely say:

When no external torque acts on a system, its angular momentum remains constant. Is the statement true ? Should kinetic energ of rotation of the system remain constant ? If yes, why , and if no, why not?

A torque of 100 N-m acting on a wheel at rest, rotates it through 200 radian in 10 s. What is the moment of inertia of the wheel?

A body starts rotating from rest. Due to a torque of 10 N.m, it completes 300 rotations in one minute. Find the moment of inertia of the body.

If torque acting upon a system is zero, the quantity that remains constant is