Al Azhar university Lama El Banna general physic

1. General Physics for Medical Sciences
Homework 5
Instructor: Dr. Hassan Ashour
Due Date: Dec 30, 2009
Solve the following questions
Q1: A 2.00 cm diameter hose carries water at 1.06 m/s. With what speed does the water exit
a 1.00 cm diameter nozzle?
Q2: By what factor will your garden watering time be cut if you switch from a 3/8 inch
diameter hose to a 5/8 inch hose? Assume nothing else is changed.
Q3: A patient is to be given a blood transfusion. If the inside diameter of the 4.0 cm long
needle is 0.40 mm, the blood pressure in the arm is 2400 Pa, and the required flow is 4.0
cm³/min, how high h should the bottle be placed? (ρ = 1050 kg/m³, η =0.0040 Pa·s)
Q4: A jet pilot pulls his plane out of dive in such a way that his upward acceleration is 3 g’s.
What you predict as the blood pressure in the brain?
Q5: The aorta in humans has a diameter of about 2 cm and at certain times, the blood speed
through it is about 55 cm /s. What is the type of flow? Find also the flow resistance over 30
cm long segment and the power for dissipating the blood through this segment
Q6: The radius of an artery is increased by a factor of 1.5 (a) the pressure drop remains the
same, what happens to the flow rate? (b) If the flow rate stays the same, what happens to the
pressure drop? (Assume laminar flow).