Final answer:
The external pressure felt at section 2 is 1.01x10^5 Pa.
Step-by-step explanation:
To calculate the external pressure felt at section 2, we can use Bernoulli's equation, which states that the sum of the pressure, kinetic energy per unit volume, and potential energy per unit volume is constant along a streamline:
P + 0.5
h_o v^2 +
h_o gh = constant
Given that section 1 has a speed (v1) of 10 m/s and a cross-sectional area (A1) of 0.126 m^2, and section 2 has a speed (v2) of 2.80 m/s and a cross-sectional area (A2) of 0.450 m^2, and assuming the height (h) is the same for both sections, we can set up the equation:
P1 + 0.5
h_o v1^2 = P2 + 0.5
h_o v2^2
Given that P1 is 1.01x10^5 Pa, we can rearrange the equation and solve for P2:
P2 = P1 + 0.5
h_o(v1^2 - v2^2)
Substituting the given values, we find that the external pressure felt at section 2 is 1.01x10^5 Pa.