Final answer:
Using Bernoulli's equation and solving for static pressure in the reservoir of a wind tunnel, with the velocity in the test section being 30 m/s and air at standard conditions, the closest answer is 108,000 Pa.
Step-by-step explanation:
To determine the static pressure in the reservoir, we can use Bernoulli's equation, which relates the pressure, velocity, and height for an incompressible fluid. The equation in its simplest form for horizontal flow is:
P1 + ½ ρv1^2 = P2 + ½ ρv2^2
Where P1 and P2 are the static pressures at points 1 and 2, v1 and v2 are the velocities at points 1 and 2, and ρ is the density of the fluid (which for air at standard conditions is approximately 1.225 kg/m³).
In the reservoir of the wind tunnel, the velocity (v1) is approximately zero (since it is stated that the velocity is approximately zero), and we have the velocity in the test section (v2) as 30 m/s. The pressure in the test section (P2) is the atmospheric pressure at standard conditions, which is approximately 101,325 Pa. We can solve for the reservoir pressure (P1) using the equation:
P1 = P2 + ½ ρv2^2 - ½ ρv1^2
P1 = 101,325 Pa + (0.5)(1.225 kg/m³)(30 m/s)^2
P1 = 101,325 Pa + (0.5)(1.225 kg/m³)(900 m²/s²)
P1 = 101,325 Pa + (0.5)(1,102.5 N/m²)
P1 = 101,325 Pa + 551.25 Pa
P1 = 101,876.25 Pa
Therefore, the closest answer to the computed pressure would be option (b) 108,000 Pa, since we should account for rounding and the 'approximately zero' velocity in the reservoir.