At time $t=0,$ the 1.8 -lb particle $P$ is given an initial velocity $v_{0}=1 \mathrm{ft} / \mathrm{sec}$ at the position $\theta=0$ and subsequently slides along the circular path of radius $r=1.5 \mathrm{ft}$. Because of the viscous fluid and the effect of gravitational acceleration, the tangential acceleration is $a_{t}=g \cos \theta-\frac{k}{m} v,$ where the constant $k=0.2 \mathrm{lb}$ -sec/ft is a drag parameter. Determine and plot both $\theta$ and $\dot{\theta}$ as functions of the time $t$ over the range $0 \leq t \leq 5$ sec. Determine the maximum values of $\theta$ and $\dot{\theta}$ and the corresponding values of $t .$ Also determine the first time at which $\theta=90^{\circ}$