To compensate and keep angular momentum constant, the washer's angular velocity has to increase. The reverse happens when you loosen the string and allow the washer to move out farther.

At t 2, the angular velocity is zero, with a non-zero (positive) angular acceleration. At that time, the direction of rotation for BC is changing from CW to CCW. In summary, you should never assume ...

You can use angular momentum to describe everything from fidget spinners to back flips to interstellar asteroids. Let's see how it works.