Amodel propeller 1 m in diameter is tested in a wind tunnel. air approaches the propeller at 50 m=s when it rotates at 1800 rpm. the thrust and torque measured under these conditions are 100 n and 10 nm, respectively. a prototype eight times as large as the model is to be built. at a dynamically similar operating point, the approach air speed is to be 130 m=s. calculate the speed, thrust, and torque of the prototype propeller under these conditions, neglecting the effect of viscosity but including density

statement #3 on andre"s list is false.

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me