- #1

Nova_Chr0n0

- 16

- 3

- Homework Statement
- (a) Calculate the difference in blood pressure between

the feet and top of the head for a person who is 1.65 m tall. (b)

Consider a cylindrical segment of a blood vessel 2.00 cm long and

1.50 mm in diameter. What additional outward force would such a

vessel need to withstand in the person’s feet compared to a similar

vessel in her head?

- Relevant Equations
- P = F/A

I've already got the correct answer in letter (a), which is 17140.2 Pascals. My question will be focusing about the letter b of the question and here is my solution:

(b)

P = F/A

F = P*A

My understanding about this problem is I have to use the pressure that I got in letter (a) to calculate the force needed by the blood vessel to withstand 17140.2 Pascals

P = 17140.2 Pa

Diameter = 1.5 x 10^-3 m (converted to meter)

height = 0.02 m (converted to meter)

Area = πr^2

Area = π[(1.5 x 10^-3)/2]^2

Area = 1.767 x 10^-6 m^2

F = 17140.2(1.767 x 10^-6)

F = 0.030 N

When I tried to look for the answer, I found 1.61 N as the final force. I think I've got the area calculation wrong. Isn't the area needed to solve the problem is the one that the force makes contact with? In the cylindrical segment stated in the problem, I've assumed that the force would be in contact with its base area, which is just the circle. Is my understanding about the area needed completely wrong? Please enlighten me. Thanks!

(b)

**FORMULA:**P = F/A

F = P*A

My understanding about this problem is I have to use the pressure that I got in letter (a) to calculate the force needed by the blood vessel to withstand 17140.2 Pascals

**Given:**P = 17140.2 Pa

Diameter = 1.5 x 10^-3 m (converted to meter)

height = 0.02 m (converted to meter)

**Solution:**

>> Getting the area>> Getting the area

Area = πr^2

Area = π[(1.5 x 10^-3)/2]^2

Area = 1.767 x 10^-6 m^2

**>> Solving for the Force**F = 17140.2(1.767 x 10^-6)

F = 0.030 N

When I tried to look for the answer, I found 1.61 N as the final force. I think I've got the area calculation wrong. Isn't the area needed to solve the problem is the one that the force makes contact with? In the cylindrical segment stated in the problem, I've assumed that the force would be in contact with its base area, which is just the circle. Is my understanding about the area needed completely wrong? Please enlighten me. Thanks!