A ferris wheel is 25 meters in diameter and boarded at ground level. The wheel makes one full rotation every 6 minutes, and at time $t = 0$ you are at the 9 o'clock position and ascending. Let $f(t)$ denote your height (in meters) above ground at $t$ minutes. Find a formula for $f(t)$.
$f(t) =$ help (formulas)