Assignment:
Problems:
1. Assume that a tibia is a hollow cylinder with a diameter of 2.5 cm and a thickness of 0.6 cm. What is the first (area) moment of inertia for this tibia? Hints: Sketch out a cross-section of the tibia to find the inner and outer radii; your answer should have units of cm4.
2. A rod of unknown material has an original length of 3 m and cross-section 0.01 m2. When stretched with a force of 250 N, the rod's length increases by 0.2 cm. What are the stress, strain, and modulus of elasticity for this material? Hint: Pay attention to the units.
3. How is the stress value computed from a strain energy density function?
4. Refer to the diagram below to answer the following questions. LVP, AP, and LAP are left ventricular pressure, aortic pressure, and left atrial pressure, respectively.
(a) What is the peak pressure drop across the aortic valve during systole?
(b) What are the systolic and diastolic pressures in the body?
(c) What condition could explain the irregularities seen in the diagram?
- (a) Aortic valve stenosis
- (b) Aortic valve regurgitation
- (c) Mitral valve stenosis
- (d) Mitral valve regurgitation
- (e) This is a normal heart
5. An ultrasound technician is attempting to measure the blood velocity in a large artery using Doppler ultrasound as shown in the figure below. The box marked "T" is the transducer. The peak blood velocity in the artery is 0.8 m/s.
(a) What will be the measured velocity of the blood (no math necessary)?
(b) Explain why this is or is not an ideal placement for the transducer.
6. Refer to the figure below to answer the following questions. Flow travels from an arteriole (resistance 8) into two capillary beds (resistance 6 and 3) and into a venule (resistance 2). Note that units have been eliminated for simplicity.
(a) What is the total resistance in this group of vessels?
(b) What is the flow rate at the outlet?
(c) What is the pressure at the outlet?