Physics

Problem

The pointer on a circular dial rotates

120^{\circ}

clockwise, pauses, and then rotates

120^{\circ}

counter-clockwise back to its original orientation. The entire motion takes

4.0\,\text{s}

. If counter-clockwise rotation is defined as positive, which statement best describes the pointer’s average angular velocity over the

4.0\,\text{s}

interval? a)

+0.52\,\text{rad/s}

because only the counter-clockwise part is taken as the displacement. b)

-0.52\,\text{rad/s}

because only the initial clockwise rotation is considered. c)

0\,\text{rad/s}

because the net angular displacement is zero. d) Cannot be determined because the instantaneous angular velocities during each part are not given.