a)The ball's maximum height above ground is 25.10 m
b)The ball's speed on its way down is 10 m/s
c)The impact speed on the ground is 22.1 m/s
Given,
Initial speed of ball = 10m/s
Height of ball above the ground = 20 m
a)
To determine ball's maximum height above the ground, use newton's equation of motion,
By using 2nd equation of motion,
[tex]v^2-u^2=2as[/tex]
Where,
v= final speed = 0
u= initial speed = 10m/s
a=acceleration, here a= -g= [tex]-9.8 m/s^2[/tex] (because ball is moving against the gravity i.e. upwards)
s= displacement
[tex]0-10^2=2(-9.8)s\\\\-100=-19.6s\\\\s=5.1 m[/tex]
Hence, the ,maximum height above the ground is h=5.1+20=25.1 m
b)
Determine the Ball's speed as it passes the window on its way down
[tex]v^2 = u^2 + 2as[/tex]
where ; u = 0 , a =g= [tex]9.8 m/s^2[/tex], s = 5.1 m
Hence ;
[tex]v^2 = 0 + 2 ( 9.81 ) * 5.1 \\\\ v = 10 m/s[/tex]
c)
The speed of impact can be determined by newton's 2nd law of motion's equation,
[tex]v^2-u^2=2as\\\\[/tex]
Here, u=0(as we are finding final speed) , a=g=9.8 and s=25.1 m(maximum height reached by the ball)
[tex]v^2-0=2(9.8)25.1\\\\v^2=491\\\\v=22.1 m/s[/tex]
Thus, the speed of impact on the ground is 22.1 m/s.
To learn more about newton's law of motion refer here
https://brainly.com/question/2437899
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