10.7 Exercise 1

The fan blades on a jet engine have a moment of inertia $30.0 \left( \text{kg}-\text{m}\right)^{2}$. In 10 s, they rotate counterclockwise from rest up to a rotation rate of 20 rev/s. (a) What torque must be applied to the blades to achieve this angular acceleration? (b) What is the torque required to bring the fan blades rotating at 20 rev/s to a rest in 20 s?