A truck is traveling 20m/s accelerates 3 m/s^2 for 4 seconds how far did it travel while it was accelerating. Using guess method

v = 20m\s

a = 3m\s^2

t = 4sec

Firstly we have to find u

a =

3m\s =

12m\s = 20 - u

20 - u = 12m\s

- u = -8

u = 8

Now we can easily find distance by using second equation of motion

s = ut + 1\2 at^2

s = 8(4) + 1\2(3)(16)

s = 32 + 24

s = 56

So distance is 56 m\s hope it helps