Physics

Problem

Students record the angular velocity of a rotor and describe their observations as follows: • From

t=0

4\,\text{s}

\omega

increases steadily. • From

t=4

8\,\text{s}

\omega

remains constant. • From

t=8

10\,\text{s}

\omega

increases again. • From

t=10

12\,\text{s}

\omega

decreases. During which time interval is the net external torque on the rotor most likely closest to zero? a)

8\text{–}10\,\text{s}

4\text{–}8\,\text{s}

0\text{–}4\,\text{s}

10\text{–}12\,\text{s}