Answer:
- The maximum height reached by the ball is 45.92 m
- Time taken to fall down to half of its height is 2.2 s
Explanation:
Given;
initial velocity of the ball, u = 30 m/s
final velocity of the ball at the highest point, v = 0
The maximum height reached by the ball is calculated as;
v² = u² - 2gh
where;
h is the maximum height reached by the ball
0 = 30² - (2 x 9.8)h
19.6h = 900
h = 900 / 19.6
h = 45.92 m
Time taken to fall to half of its height is calculated as;
when falling down, the final velocity v becomes the initial velocity = 0.
Apply the following kinematic equation;
h = ut + ¹/₂gt²
h = 0 + ¹/₂gt²
h = ¹/₂gt²
where;
h = 45.92 m is the maximum height reached
half of h = 45.92 / 2 = 22.96 m
22.96 = ¹/₂gt²

The wave height is equal to twice the amplitude of the wave.
The wave height of a wave of given wave with amplitude, period and wavelength is equal to twice the amplitude of the wave.
The amplitude of a wave is the maximum displacement of the wave, starting from the zero position of the wave. The wave height measures twice the maximum displacement of the wave.
Thus, we can conclude that the wave height is equal to twice the amplitude of the wave.
Learn more here:brainly.com/question/21431500
All you need to do is to convert the velocity to meters per hour. Then multiply by 0.4 hours. I guess the answer was rounded up.