Respuesta :
Answer:
The initial velocity of the ball is 39.2 m/s in the upward direction.
Explanation:
Given:
Upward direction is positive. So, downward direction is negative.
Tota time the ball remains in air (t) = 8.0 s
Net displacement of the ball (S) = Final position - Initial position = 0 m
Acceleration of the ball is due to gravity. So, [tex]a=g=-9.8\ m/s^2[/tex](Acting down)
Now, let the initial velocity be 'u' m/s.
From Newton's equation of motion, we have:
[tex]S=ut+\frac{1}{2}at^2[/tex]
Plug in the given values and solve for 'u'. This gives,
[tex]0=8u-0.5\times 9.8\times 8^2\\\\8u=4.9\times 64\\\\u=\frac{4.9\times 64}{8}\\\\u=4.9\times 8=39.2\ m/s[/tex]
Therefore, the initial velocity of the ball is 39.2 m/s in the upward direction.
