In the figure below, a constant horizontal force Fapp of magnitude 17 N is applied to a wheel of mass 8 kg and radius 0.70 m. The wheel rolls smoothly on the horizontal surface, and the acceleration of its center of mass has magnitude 0.75 m/s2.

(a) In unit-vector notation, what is the frictional force on the wheel?
1 N

(b) What is the rotational inertia of the wheel about the rotation axis through its center of mass?
2 kg·m2