Chapter R.1, Problem 29E

Snowboarding in the half-pipe. Shaun White, “The Flying Tomato,” won a gold medal in the 2010 Winter Olympics for snowboarding in the half-pipe. He soared an unprecedented $25\text{ft}$ above the edge of the half-pipe (which was still the world record in 2017). His speed $v(t)$, in miles per hour, upon reentering the pipe can be approximated by $v(t)=10.9t$, where $t$ is the number of seconds for which he was airborne. White was airborne for $2.5\text{sec}$.

(Source: “White Rides to Repeat in Halfpipe, Lago Takes Bronze,” Associated Press, 2/18/2010.) How fast was he going when he reentered the half-pipe?