http://schoolsolver.com/questions/20-In-a-certain-experiment-a-small-radioactive-source-must-move-at-selected-extremely-slow-speeds-This-motion-is-accomplished-by-fastening-the-source-to-one-end-of-an-aluminum-rod-and-heating-the-central-section-of-the-rod-in-a-controlled-way-If-the-effective-heated-section-of-the-rod-has-length-d=2.00-cm-at-what-constant-rate-must-the-temperature-of-the-rod-be-changed-if-the-source-is-to-move-at-a-constant-speed-of-100-nm/s/