Answer:
v = 39.6 m/s (first answer option)
Explanation:
Use conservation of mechanical energy.
The starting is completely potential energy and the final is all kinetic energy:
[tex]m*g*h=\frac{1}{2}*m*v^2\\g * h=\frac{1}{2} v^2\\9.8*80=\frac{1}{2} v^2\\v^2=1568\\v\approx 39.6\,\,m/s[/tex]
which agrees with the first answer shown.
