The table shows the position of a motorcyclist after accelerating from rest.
Table can't copy
(a) Find the average velocity for each time period:
(i) $[2,4]$
(ii) $[3,4]$
(iii) $[4,5]$
(iv) $[4,6]$
(b) Use the graph of $s$ as a function of $t$ to estimate the instantaneous velocity when $t=3$.