Question

how do you do the seconds?

Answer 1

The question is either incomplete or there is a mistake in the question.
We cannot calculate distance travelled (S) given acceleration (a) and time (t) alone.
We need to know the initial velocity, (vi), which is zero if it starts from rest, or final velocity (vf).
The kinematics equation is:
1. given a, t and vi
\(S=v_i t+(a/2)t^2\)
2. given a, t and vf.
\(S=(v_f-at)t+(a/2)t^2)=v_f t-(a/2)t^2\)

The question supplies a=3.55 m/s^2, t=8.5 s.
State and assume a value for vi or vf to find distance travelled.