From conservation of momentum, the ram force can be calculated similarly to rocket thrust:
F = d(mv)/dt = vdm/dt.
In other words, the force needed to decelerate the wind equals the force that would be needed to produce it.
v = 120/3.6 = 33.33 m/s
dm/dt = v*area*density
dm/dt = (33.33)*((45)*(75))*(1.3)
dm/dt =
146235.375 kg/s
F = v^2*area*density
F = (33.33)^2*((45)*(75))*(1.3) =
4874025 N
This differs by a factor of 2 from Bernoulli's equation, which relates velocity and pressure difference in reference not to a head-on collision of the fluid with a surface but to a fluid moving tangentially to the surface. Also, a typical mass-based drag equation, like Bernoulli's equation, has a coefficient of 1/2; however, it refers to a body moving through a fluid, where the fluid encountered by the body is not stopped relative to the body (i.e., brought up to its speed) like is the case in this problem.
