Given v_in = 20 m/s and a = 3 m/s2, assuming that the body
moves at constant acceleration, the motion is modeled by the equation:
s(t) = (v_in)t + (1/2)a(t^2)
where s(t) is the distance traveled
substituting the given,
s(t) = 20t + (3/2)(t^2)
at t = 3
s(t) = 20(3) + (3/2)(3)^2
= 73.5 m
