Penny needs to be taught some physics by Sheldon. ;-) Meanwhile, Howard enjoys his new GF who enjoys Leonard's experiments.
Although some early quotes resembling Sheldon's own analyses indicated that there was a chance for her, "F=ma" turned out to be well above her head already. ;-)
However, Penny easily learns the unoriginal merits of Leonard's experiment from Sheldon - who has also been repeated by Howard. The result is not lovely. :-)