Step-by-step explanation:
The WORK required to stop the truck is equal to the initial Kinetic Energy of the truck ( 1/2 m v^2)
1/2 mv^2 = 1/2 * 2000 * 30^2 = 900 000 J
Distance travelled in 10 seconds is
d = vot - 1/2 at^2 where a = 30 m/s / 10 s = 3 m/s^2
= 30 (10) - 1/2 ( 3)(10^2) = 150 meters
Work = F * d
900 000 = F * 150
F = 6000 N