Answer:
approximately 19.8 m/s
If using g = 10 m/s^2, the answer rounds to 20 m/s
Explanation:
You can use the kinematic formula that relates distance covered, velocities and acceleration (without time dependence) given by:
[tex]v_f^2-v_i^2=2\,*\,a\,*displacement[/tex]
which in our case becomes:
[tex]v_f^2-0=2\,*\,(9.8\,\frac{m}{s^2}) \,*(20\,m)\\v_f^2=392\\v_f\approx 19.8\,\frac{m}{s}[/tex]
If using g = 10 m/s^2, the answer is 20 m/s
