Firstly we write down all known variables: Initial speed (u)=0 m/s, Acceleration (a)=3 m/s2, Time (t)=5s. Final velocity (v)=?Therefore, the equation chosen to solve the problem would be: v=u+at. Substituting known variables into equation gives: v=0+(3*5). Giving a final answer: v=15 m/s.