1. 9.04 s
We can find the time taken for the steel ball to reach the ground by using the SUVAT equation:
[tex]d = ut + \frac{1}{2}gt^2[/tex]
where
d = 400 m is the distance
u = 0 is the initial velocity of the ball
g = 9.8 m/s^2 is the acceleration of gravity
t is the time
Solving the formula for t, we find the time taken for the ball to reach the ground:
[tex]t=\sqrt{\frac{2d}{g}}=\sqrt{\frac{2(400)}{9.8}}=9.04 s[/tex]
2. 88.6 m/s
The final velocity of the ball before it reaches the ground can be found by using the equation
v = u + gt
where
u is the initial velocity
g is the acceleration of gravity
t is the time
Here we have
u = 0
g = 9.8 m/s^2
Substituting the time of flight, t = 9.04 s, we find the final velocity:
[tex]v=0+(9.8)(9.04)=88.6 m/s[/tex]
