Answer:
c) 10.7m/s
Explanation:
From the exercise we know that at 5m the ball is traveling at 4m/s
To calculate its initial velocity we need to solve the following equation:
[tex]v_{y}^{2}=v_{oy}^{2}+2g(y-y_{o})[/tex]
Since the initial height is 0
Solving for [tex]v_{o}[/tex]
[tex]v_{oy}=\sqrt{v_{y}^{2}-2gy}=\sqrt{(4m/s)^2-2(-9.8m/s^2)(5m)}=10.7m/s[/tex]