Answer:
52 m/s
Explanation:
By the conservation of energy, the potential energy at the top will be equal to the kinetic energy at the bottom, so
[tex]\begin{gathered} E_i=E_f_{}_{} \\ PE_i=KE_f_{} \\ \text{mgh}=\frac{1}{2}mv^2 \end{gathered}[/tex]Where m is the mass, g is the gravity, h is the height and v is the speed. Solving for the speed v, we get:
[tex]\begin{gathered} 2\text{mgh}=mv^2 \\ \frac{2\text{mgh}}{m}=v^2 \\ 2gh=v^2 \\ v=\sqrt[]{2gh} \end{gathered}[/tex]Then, replacing g = 9.8 m/s² and h = 140 m, we get:
[tex]\begin{gathered} v=\sqrt[]{2(9.8)(140)} \\ v=52.38\text{ m/s} \end{gathered}[/tex]Therefore, the answer is 52 m/s
