Answer:
u=8.868 m/s
Explanation:
The displacement of the ball is 4 meters
The final speed of the ball is 0.5 m/s
The initial speed of the ball is to be calculated. Using the equation of the rectilinear motion,
[tex]v^{2} =u^{2} +2as[/tex]
Plugging the values in the above expression,
[tex]\\0.5^{2} =u^{2} +2*(-9.8)*4\\\\u^{2} =78.4+0.25\\\\u^{2} =78.65\\\\u=8.868 m/s[/tex]