Chapter 10 - Rotational Kinematics and Energy - Problems and Conceptual Exercises - Page 324: 19

(a) $\Delta \theta=69\ rev$ (b) $\Delta \theta=52\ rev$

(a) As $\Delta \theta=\frac{1}{2}(\omega_f+\omega_i)t$ We plug in the known values to obtain: $\Delta \theta=\frac{1}{2}(0+0.96)(2.4min\times 60\frac{s}{min})$ $\Delta \theta=69\ rev$ (b) (As $\Delta \theta=\frac{1}{2}(\omega_f+\omega_i)t$ We plug in the known values to obtain: $\Delta \theta=\frac{1}{2}(0.48+0.96)(1.2min\times 60\frac{s}{min})$ $\Delta \theta=52\ rev$