Answer:
Explanation:
From the question we are told that
The mass of the tennis ball is [tex]m = 0.060 \ kg[/tex]
The speed is [tex]u = 15 \ m/s[/tex]
The initial height of the ball is [tex]h_o = 2.2 \ m[/tex]
The height considered is [tex]h = 9.5 \ m[/tex]
Generally the time taken to reach the considered height is mathematically evaluated from the equation of motion as follows
[tex]h = h_o + ut - \frac{1}{2} gt^2[/tex]
=> [tex]9.5 = 2.2 + 15t - \frac{1}{2} * 9.8 t^2[/tex]
=> [tex]7.3 = 15t - 4.9t^2[/tex]
=> [tex]4.9t^2 -15t + 7.3[/tex]
solving the above equation using quadratic formula
[tex]t= 0.6070 \ s[/tex] and [tex]t_1 = 2.454 \ s[/tex]
Generally from kinematic equation we have that
[tex]v = u - gt[/tex]
=> [tex]v= 15 - 9.8 * 0.6070[/tex]
=> [tex]v= 9.0514 \ m/s[/tex]
Note if we had used the second values of time the velocity at 9.5 \ m would have been negative which is not correct given that at maximum height velocity is zero