Afan that can provide air speeds of up to 40 m/s is to be used in a low-speed wind tunnel with atmospheric air at 17◦c. if one wishes to use the wind tunnel to study flat-plate boundary layer behaviour up to reynolds numbers of rex = 107 , what is the minimum plate length that should be used? at what distance from the leading edge would transition, from laminar to turbulent flow, occur if the critical reynolds number were rex, c = 5 × 105 ?

Aforce of 200 n is applied to an input piston of cross-sectional area 2 sq. cm pushing it downward 2.8 cm. how far does the output piston of cross-sectional area 12 sq. cm move upward? show all work.

Astone is thrown into a pond. what happens to the amplitude of the resulting waves as they get farther from the point where the stone hit the water? explain.

Very large accelerations can injure the body, especially if they last for a considerable length of time. one model used to gauge the likelihood of injury is the severity index ( ), defined as =/ . in the expression, is the duration of the accleration, but is not equal to the acceleration. rather, is a dimensionless constant that = the number of multiples of that the acceleration is equal to. in one set of studies of rear-end collisions, a person's velocity increases by 13.7 km/h with an acceleration of 36.0 m/s2 . let the + direction point in the direction the car is traveling. what is the severity index for the collision?