ANSWER:
3.47 m/s
STEP-BY-STEP EXPLANATION:
We can calculate the velocity value assuming that the kinetic energy is equal to potential, therefore:
[tex]\begin{gathered} PE=KE \\ mgh=\frac{1}{2}mv^2 \end{gathered}[/tex]By losing 18% of initial energy, it means that the energy value is 82% (100-18), which means that the speed also represents 82%.
We replace the values and calculate for v, like this:
[tex]\begin{gathered} 0.82\cdot mgh=\frac{1}{2}mv^2 \\ v=\sqrt[]{2gh} \\ v=\sqrt[]{0.82\cdot2\cdot9.8\cdot0.75} \\ v=3.47\text{ m/s} \end{gathered}[/tex]