The displacement (in meters) of a particle moving in a straight line is given by s=21t27t+16, where t is measured in secords. (a) Find the average velocity (in m/s) over each time interval. (i) [4,8] (ii) [6,8] (iii) {8,10} (i) {8,12} m/s (b) Find the ingtantaneous veiocity ( in m/b) when t=8. m/s (c) Draw the graph of s as a function of t and draw the secant lines whose slopes are the average velocities in part (a). Then seiect the graph of s with the tangent line whose slope is the instantaneous velocity in part (b)