A displacement boat (generally a moving object held up by buoyancy of the water) generates a wave that travels alongside at the speed of the boat with the first wave crest at the bow of the boat. Because the wavelength increases with the boat's speed, above a certain speed the second crest appears astern of the boat, so that the boat must travel uphill on the wave it creates. If it lacks the power to get over the top of this wave, its speed is limited to roughly the speed of a wave with the length of the boat. Hence we have the following rule of thumb: The maximum speed of a modestly powered boat is approximately equal to (actually, a little faster than) the wave whose wavelength equals the length of the boat measured at the waterline. Empirically, the propagation velocity of water waves is

In a wind tunnel the speed changes as the cross sectional area of the tunnel changes. if the speed in a 6' x 6' square test section is 100 mph, what was the speed upstream of the test section where the tunnel measured 20' x 20'? use conservation of mass and assume incompressible flow. conservation of mass requires that as the flow moves through a path or a duct the product of the density, velocity and cross sectional area must remain constant; i.e., that ova-constant. a model is being tested in a wind tunnel at a speed of 100 mph if the flow in the test section is at sea level standard conditions, what is the pressure at the model's stagnation point? (a) the tunnel speed is being measured by a pitot-static tube connected to a u- tube manometer. what is the reading on that manometer in inches of water? (b) at one point on the model a pressure of 2058 psf is measured. what is the local airspeed at that point?

Ahypothesis is? close agreement by competent observers of observations of the same phenomena. a guess that has been tested over and over again and always found to be true. an educated guess that has yet to be proven by experiment. the long side of a right triangle. a synthesis of a large collection of information that includes guesses.

Order the sequence of ideas that lead to marie curies discovery of radioactive elements number the events in chronological order starting with the oldest