$(5)$ Chapter $8$ Conceptual Question $7.$ A small fan has blades that have a radius of $0\mathrm{.}0800$ m $.$ When the fan is turned on$,$ the tips of the blades have a tangential acceleration of $25\mathrm{.}0\frac{m}{s^2}$ as the fan comes up to speed. What is the angular acceleration $$ of the blades $(ra\frac{d}{s^2})?$

$(5)$ Chapter $8$ Problem $7.$ A jet is circling an airport control tower at a distance of $18\mathrm{.}0$ km $.$ An observer in the tower watches the jet cross in front of the moon. As seen from the tower, the moon subtends an angle of $9\mathrm{.}04{10}^{-3}$ radians. Find the distance traveled $($in meters$)$ by the jet as the observer watches the nose of the jet cross from one side of the moon to the other.