$11-141$

At a given instant in an airplane race, airplane A is flying horizontally in a straight line, and its

speed is being increased at a rate of $6\frac{m}{s^2}.$ Airplane B is flying at the same altitude as airplane

A and, as it rounds a pylon, is following a circular path of $200-m$ radius. Knowing that at a given

instant the speed of B is being decreased at a rate of $2\frac{m}{s^2},$ determine, for the positions shown,

$($a$)$ the velocity of $B$ relative to $A,($b$)$ the acceleration of $B$ relative to $A.$ Answers: $478$km$/$h and aB$/$A$=109\mathrm{.}6$m$/$s$^2$