Question

A truck covers 40.0 m in 7.10 s while smoothly slowing down to a final velocity of 2.75 m/s.
(a) Find the truck's original speed.

Answer 1

v = u + at
75 = u + 7.1 a
s = ut + 1/2 at^2

You can find it using this two equation method.  The original speed will be the u

hope this helps