Halliday, Resnick & Walker — Motion in Two and Three Dimensions: Problem 78

In the overhead view of Fig. 4.27, Jeeps $P$ and $B$ race along straight lines, across flat terrain, and past stationary border guard $A$. Relative to the guard, $B$ travels at a constant speed of $20.0 \text{ m/s}$, at the angle $\theta_2 = 30.0^\circ$. Relative to the guard, $P$ has accelerated from rest at a constant rate of $0.400 \text{ m/s}^2$ at the angle $\theta_1 = 60.0^\circ$. At a certain time during the acceleration, $P$ has a speed of $40.0 \text{ m/s}$. At that time, what are the (a) magnitude and (b) direction of the velocity of $P$ relative to $B$ and the (c) magnitude and (d) direction of the acceleration of $P$ relative to $B$?