Pressure and Bernoulli + Continuity

In summary, the conversation involves a question about the pressure in a narrow pipe compared to a wide pipe, given the flow speed and pressure in the wide pipe. The equations used to solve the problem are also provided. However, the correct answer does not match any of the options given. It seems there may be an error in the options.
  • #1
physgrl
138
0

Homework Statement



Water flows through a horizontal tapered pipe. At the wide end its speed is 4.0 m/s and at the narrow end it is 5.0 m/s. The pressure in the wide pipe is 2.5 x 10^5 Pa. What is the pressure in the narrow pipe?

a. 2.5 x 10^2 Pa
b. 3.4 x 10^3 Pa
c. 4.5 x 10^3 Pa
d. 2.3 x 10^5 Pa
e. 8.0 x 10^5 Pa

Homework Equations



P1+1/2*ρ*v12 = P2+1/2*ρ*v22
A1*v1=A2*v2

The Attempt at a Solution



1-wide
2-narrow

P1+1/2*ρ*v12 = P2+1/2*ρ*v22

2.5 x 10^5 Pa + 1/2*1000kg/m3*(4m/s)2=P2 + 1/2*1000kg/m3*(5m/s)2

2.5 x 10^5 Pa + 1/2*1000kg/m3*(4m/s)2- 1/2*1000kg/m3*(5m/s)2=P

2.5 x 10^5 Pa + 1/2*1000kg/m3*[(4m/s)2-(5m/s)2]=P

2.455x10^5 Pa=P

the answer is not in the options :s can someone tell me what i did wrong?
 
Last edited:
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  • #2
I agree with your answer. Looks like an error in supplied answer.
 
  • #3
thanks! :)
 

Related to Pressure and Bernoulli + Continuity

1. What is pressure and how is it measured?

Pressure is defined as the force per unit area exerted by a fluid. It is measured using a variety of units, including pascals (Pa), atmospheres (atm), and pounds per square inch (psi).

2. What is Bernoulli's principle and how does it relate to pressure?

Bernoulli's principle states that as the velocity of a fluid increases, the pressure exerted by the fluid decreases. This is because as the fluid moves faster, it exerts less force per unit area on the surfaces it comes into contact with.

3. What is the equation for Bernoulli's principle?

The equation for Bernoulli's principle is P + 1/2ρv^2 + ρgh = constant, where P is the pressure, ρ is the density, v is the velocity, g is the acceleration due to gravity, and h is the height.

4. What is the continuity equation and how is it related to pressure?

The continuity equation states that the mass flow rate of a fluid is constant throughout a pipe or channel. This means that as the velocity of the fluid decreases, the pressure increases, and vice versa.

5. How do changes in pressure affect the movement of fluids?

Changes in pressure can greatly affect the movement of fluids. For example, a decrease in pressure can cause a fluid to flow faster, while an increase in pressure can cause it to flow slower. Additionally, changes in pressure can also cause fluids to change direction or even create turbulence.

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