Final answer:
The average velocity of the oil flow in the tube is approximately 1.796 m/s.
Step-by-step explanation:
To calculate the average velocity, we can use the formula v = Q / A.
First, we need to convert the flow rate from liters per minute to cubic meters per second. There are 1000 liters in a cubic meter and 60 seconds in a minute, so the flow rate Q = 27.7 l/min is equivalent to Q = 27.7 / (1000 * 60) cubic meters per second.
The cross-sectional area of the tube is given by the formula A = πr^2, where r is the radius of the tube. Since the diameter of the tube is 7 mm, the radius is 3.5 mm or 0.0035 m. Therefore, the cross-sectional area A = π(0.0035)^2 = 0.00003848 m^2.
Now we can calculate the average velocity with the formula v = Q / A. Substituting the values, we get v = (27.7 / (1000 * 60)) / 0.00003848 = 1.796 m/s. Therefore, the average velocity of the oil flow in the tube is approximately 1.796 m/s.