The speed of propagation of the action potential (an electrical signal) in a nerve cell depends (inversely) on the diameter of the axon (nerve fiber). If the nerve cell connecting the spinal cord to your feet is 1.1 m long, and the nerve impulse speed is 18 m/s, how long does it take for the nerve signal to travel this distance?

Solution:

The time of travel is computed based on the formula

\text{time}=\frac{\text{distance}}{\text{speed}}

Therefore, the time of travel is

\begin{align*}
\text{time} & =\frac{1.1\:\text{m}}{18\:\text{m/s}} \\
& =0.0611\:\text{seconds} \ \qquad \ \color{DarkOrange} \left( \text{Answer} \right)
\end{align*}