Chapter 12 - Kinematics of a Particle - Section 12.8 - Curvilinear Motion: Cylindrical Components - Problems - Page 83: 185

$v=1.32$ m/s

$\dot{\theta}=5$ $r=100(2-\cos \theta)$ $\dot{r}=100\dot{\theta} \sin \theta = 500\sin \theta$ $\ddot{r}=500 \dot{\theta} \cos \theta = 2500 \cos \theta$ At $\theta=120$ $v_r=\dot{r}=500 \sin 120 = 433.013$ $v_\theta=r\dot{\theta}=100(2-\cos 120)(5)=1250$ $v=\sqrt{433.013^2+1250^2}=1322.9$ mm/s $=1.32$ m/s