The first graph is the energy E of an electric car versus its terminal velocity v, the second graph shows terminal velocity v versus maximum horsepower hp. The points (v,E)=$(3.2,1)$ and (hp,v)=$(17,3.2)$ are shown on the graphs. Estimate
$\displaystyle \left.\frac{dE}{dhp}\right\vert_{hp=17}=$
Include units.
Note that the gridlines on the horsepower axis are spaced every two horsepower (units = "hp"), the velocity axes are spaced every $\frac{1}{3}\frac{ft}{s}$ (units = "ft/s"), and on the energy axis they are spaced every $\frac{1}{2}$ foot pounds (units = "lbf").