Question 1029785
Average velocity over the interval 0 to 8 seconds = {{{(1/8)int(t^2-9t+18, dt, 0,8) }}}

={{{(1/8)(t^3/3 -(9/2)t^2 +18t)[0]^8 = (1/8)(8^3/3 -(9/2)8^2 +18*8)= 8^2/3 -(9/2)8 +18 = 3&1/3}}} meters per second.

The instantaneous velocity = {{{dv(t)/dt = 2t - 9}}} ==>The instantaneous velocity and speed at time 5 secs is 2*5 - 9 = 1 meter per second.