Adiffusion couple of two metals, a and b, was fashioned as shown in figure 5.1. after a 26 hour heat treatment at 1050°c (and subsequent cooling to room temperature) the concentration of a is 4.0 wt% at the 14-mm position within metal b. if another heat treatment is conducted on an identical diffusion couple, only at 711°c for 26 hours, at what position (in mm) will the composition be 4.0 wt% a? the preexponential and activation energy values for the diffusion of a in b are 2.4 × 10-4 m2/s and 154 kj/mol, respectively.

Explain why electric current cannot exist if a current doesn't have a voltage source.

Consider a double atwood machine constructed as follows: a mass 4m is suspended from a string that passes over a massless pulley on frictionless bearings. the other end of this string supports a second similar pulley, over which passes a second string supporting a mass of 3m at one end and m at the other. using two suitable generalized coordinates, set up the lagrangian and use the lagrange equations to find the acceleration of the mass 4m when the system is released. explain why the top pulley rotates even though it carries equal weights on each side.

The solid that is formed and usually sinks to the bottom of a solution is the