Answer
37.9 m
Work Step by Step
Let's take,
The velocity of the truck relative to the ground = $V_{TG}$
The velocity of the truck relative to the car = $V_{TC}$
The velocity of the car relative to the ground = $V_{CG}$
Please see the image,
Using the Pythagorean theorem, we can write,
$V_{TG}=\sqrt {V_{TGx}^{2}+V_{TGy}^{2}}=\sqrt {(V_{TC}cos52^{\circ})^{2}+(V_{CG}+V_{TC}sin52^{\circ})^{2}}$
$V_{TG}=\sqrt {(24cos52^{\circ}m/s)^{2}+(16\space m/s+24sin52^{\circ} m/s)^{2}}=37.9\space m/s$
