Question

suppose the blades of a wind turbine generator slow down in a clockwise direction. what is the sign of the average angular acceleration of the blades? notes: clockwise is negative while counterclockwise is positive. multiple choice \bigcirc positive since it is slowing down in a clockwise negative direction. \bigcirc negative since it is slowing down in a clockwise negative direction. \bigcirc the acceleration is zero since the motion is circular. \bigcirc negative at first, then positive.

Explanation:

1. The angular velocity direction (clockwise) is negative.
2. When slowing down, angular acceleration opposes angular velocity. So if velocity is negative (clockwise), acceleration must be positive to slow it (since positive and negative oppose).
3. So the angular acceleration is positive as it slows a negative - direction motion.

Answer:

A. Positive since it is slowing down in a clockwise negative direction.