Angular impulse

The angular impulse in physics is the product of the average of a briefly applied force F times the radius of a rigid body R times the brief time period δt:

where the final angular velocity is just after the impulse, and the initial angular velocity is just before the impulse.

Example

Suppose a rotating cylinder of radius R₂ is joined with a stationary cylinder of radius R₁. Both feel an impulsive force until the continue rotating without slippage at different angular velocities. The above formula permits calculation of the respective angular velocities as follows:

Thus:

But:

and:

and thus can be solved in terms of the initial angular velocity of the rotating cylinder .

See also

• Rotational mechanics
• Impulse