Final answer:
To find the average velocity over the interval 0 ≤ r ≤ R, integrate the velocity function and divide by the length of the interval. The maximum velocity can be found by substituting r = 0 into the velocity function.
Step-by-step explanation:
The average velocity over the interval 0 ≤ r ≤ R can be found by taking the average of the velocity function v(r) = (P/4ηl)(R2 - r2) with respect to r. To find the average velocity, we need to integrate v(r) over the interval 0 ≤ r ≤ R and divide by the length of the interval (R - 0). The formula for average velocity is:
Average velocity = (1/(R - 0)) * integral[(P/4ηl)(R2 - r2) dr] from r = 0 to r = R
To compare the average velocity with the maximum velocity, we can find the maximum velocity by substituting r = 0 into the velocity function v(r) = (P/4ηl)(R2 - r2).