A roller coaster $($mass $M_{RC}=519kg)$ is moving with speed of $28\mathrm{.}7\frac{m}{s}$ as it moves over a crest $22\mathrm{.}7$ m above the ground. A short timelater, the roller coaster is only $5\mathrm{.}4$ m above the ground.

Assuming that friction is negligible, what is the speed $($in $\frac{m}{s})$ of the roller coaster when it reaches the $5\mathrm{.}4$ m height?