Suppose u(x, t) measures the concentration of a substance in a moving stream (moving with velocity v). suppose the concentration u(x, t) changes both by diffusion and convection; derive the equatiorn from the fact that at any instant of time, the total mass of the material is not created or destroyed in the region [x, x + ax] hint write the conservation equation change of mass inside [x, x + ax] = change due to diffusion across the boundaries + change due to the material being carried across the boundaries

Choose a realistic problem for which these are the correct freebody diagrams. be sure that the answer that the problem requests is consistent with the diagrams shown. choose a realistic problem for which these are the correct freebody diagrams. be sure that the answer that the problem requests is consistent with the diagrams shown. a 1.0 kg block is placed on top of a 2.0 kg block. a horizontal rope pulls the 2.0 kg block across a frictionless floor with a force of 21.0 n. the coefficient between the two blocks is 0.75. does the 1.0 kg block on top slide?