For a particle with position s(t)=t2+2t metres, answer the following.
a. (i) Calculate the average velocity on the interval t=1 s to t=3 s.
b. (ii) Determine the instantaneous velocity at t=2 s.
c. (iii) State, with reason, whether the average velocity on [1,3] equals the instantaneous velocity at the midpoint of the interval.