Chapter 4, Problem 11P

Recall that the velocity of the falling parachutist can be computed by [Eq. (1.10)],

$v\left(t\right)=\frac{gm}{c}\left(1-e^{-\left(c/m\right)t}\right)$

Use a first-order error analysis to estimate the error of v at $t=6$, if $g=9.81\text{ and }m=50$ $\text{but }c=\text{12}\text{.5}\pm \text{1}\text{.5}$.