# Homework Help: Is torque required to change angular momentum?

1. Jun 4, 2007

### eyehategod

is torque required to change angular momentum?

2. Jun 4, 2007

### ice109

unless newton's first law of motion doesn't hold as far as advanced physics is concerned i'm gonna have to go with yes

3. Jun 4, 2007

### andrevdh

Yes if one considers the N1 analogy

$$\tau = I \alpha$$

which implies if the torque is zero that the angular acceleration will also be zero giving no change in angular speed.

One can object and say - what about internal forces changing the moment of inertia of an object? In such instances it is found that the angular speed adjusts to keep the angular momentum of the object constant.

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