An antenna array used in radio astronomy consists of a set of antennae equally-spaced along a north-south line. By reciprocity, the detection pattern of the antenna array is just the same as the radiation pattern as if the antennae were radiating at the same wavelength. The spacing between the antennae is smaller than the wavelength. Show that the array only receives radiation from a specific direction in the N-S plane, and that the direction can be chosen by int

Two horizontal plates with infinite length and width are separated by a distance h in the z direction. the bottom plate is moving at a velocity u. the incompressible fluid trapped between the plates is moving in the positive x-direction with the bottom plate. align gravity with positive z. assume that the flow is fully-developed and laminar. if the systems operates at steady state and the pressure gradient in x-direction can be ignored, do the following: 1. sketch your system 2. identify the coordinate system to be used. 3. show your coordinates and origin point on the sketch. list all your assumptions. 5. apply the continuity equation to your system. nts of navier stokes equations of choice to your system 7. solve the resulting differential equation to obtain the velocity profile within the system make sure to list your boundary conditions. check units of velocity 8. describe the velocity profile you obtain using engineering terminology. sketch that on the same sketch you provided in (1). 9. obtain the equation that describes the volumetric flow rate in the system. check the units.

The most important difference between a wedge and an inclined plane is a. their size b. their shape c. how they are used d. what they are made of

If an athlete runs once around a track, back to the starting line, her average velocity is zero. true or false?