Problem $3(25$ pts$)$

As the truck A shown backs up with a constant acceleration of $4f\frac{t}{s^2},$

the distal section $B$ of its boom starts to retract into its base on the truck

bed with a constant acceleration of $1\mathrm{.}6f\frac{t}{s^2}$ relative to the truck.

Determine $($a$)$ the acceleration of section $B$ and $($b$)$ the velocity of section

$B$ when $t=2s($if all motion starts at $t=0s).$ Note that the $50$ angle

shown does not change. Report both the magnitude and direction $$ for

each vector, with $$ defined as shown.