[填空题]
(a) For a bicycle, how is the angular speed of the17m.9mp:kf ucm svyz5 rear wheebg)nfm(wux7;e4( 6a ,tuv+ e,vcmiyv l ($\omega_R$) related to that of the pedals and front sprocket ($\omega_F$) Fig. 8–52? That is, derive a formula for ($\omega_R$)/($\omega_F$) Let $N_F$ and $N_R$ be the number of teeth on the front and rear sprockets, respectively. The teeth are spaced equally on all sprockets so that the chain meshes properly.
(b) Evaluate the ratio ($\omega_R$)/($\omega_F$) when the front and rear sprockets have 52 and 13 teeth, respectively,
(c) when they have 42 and 28 teeth.
