Amarching band consists of rows of musicians walking in straight, even lines. when a marching band performs in an event, such as a parade, and must round a curve in the road, the musician on the outside of the curve must walk around the curve in the same amount of time as the musician on the inside of the curve. this motion can be approximated by a disk rotating at a constant rate about an axis perpendicular to its plane. in this case, the axis of rotation is at the inside of the curve. consider two musicians, alf and beth. beth is four times the distance from the inside of the curve as alf.

knowing that if beth travels a distance s during time δt, how far does alf travel during the same amount of time= (1/4)s

if alf moves with speed v, what is beth's speed? speed in this case means the magnitude of the linear velocity, not the magnitude of the angular velocity.

a)4v b) v c) v/4

The inside surface of a cylindrical-shaped cave of inner diameter 1.0 m is continuously covered with a very thin layer of water. the cave is very long and it is open on both ends. the water on the cave surface is at a constant temperature of 15.5 °c. the cave is constantly exposed to wind such that 15.5 °c air flows through the cave at 4.5 m/s. the kinematic viscosity of the air is 14.66 x 10-6 m2/s and the molecular diffusion coefficient of water vapor in the air is 0.239 x 10-4 m2/s. because the cave diameter is so large, the flow of wind down the length of the cave, in the x direction, can be treated like it is external flow and the cave surface can be approximated as flat where appropriate. calculate the x value, in a) the transition to turbulent flow occurs at rex meters, where the air flow transitions from laminar to turbulent along the inside surface of the cave b) calculate the x value, in meters, where the bulk steady state concentration of water vapor in the air flowing in the cave is 10% of the saturation concentration. assume the air at the surface of the water layer is 100% saturated with water vapor. assume the wind entering the cave contained no moisture before it entered the cave. take into account the transition from laminar to turbulent flow when solving part b