A cork $$oating on a lake bobs up and down as a wave passes. The cork completes $4\mathrm{.}004\mathrm{.}00$cycles in $8\mathrm{.}008\mathrm{.}00$s$.$ The wave peaks are $21\mathrm{.}021\mathrm{.}0$cm apart. Find the speed of the wave.

Part $1+$

Give the equation used for finding the speed of a wave in terms of its wavelength $($$)$ and its frequency $($ff$).$

$($Enter as lambda$)$

Part $2$

Find the speed of the wave.