Answer:
28,699m
Step-by-step explanation:
The force to make the box move should be μs.N=μs.m.g=m.|a|
then,
|a|=μs.g
Being
μs coefficient of static friction,
N the force made by the truck on the box caused by the gravity force,
m the mass,
g the acceleration of gravity
and a the acceleration of the truck.

as the truck is stopping, the acceleration is negative. then,





28,699m