Aflat, horizontal uniform plank is supported underneath by a triangular wedge which itself rests on flat, level ground. an object that has the same weight as the plank is placed on the left end of the plank. where the wedge must be placed under the plank in order for the system to be in equilibrium?

a. 1/6 the length of the plank from the left end
b. 1/5 the length of the plank from the left end
c. 1/4 the length of the plank from the left end
d. 1/3 the length of the plank from the left end

How does convection affect our atmosphere? our layers of earth? our oceans?

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.

Positrons are spontaneously emitted from the nuclei of