Answer:
most commonly occurs because of the frequent pumping of water from the ground.
Explanation:
Given that,
Height =1.5 m
Angle = 45°
We need to find the greater speed of the ball
Using conservation of energy
![P.E_{i}+K.E_{f}=P.E_{f}+K.E_{f}](https://tex.z-dn.net/?f=P.E_%7Bi%7D%2BK.E_%7Bf%7D%3DP.E_%7Bf%7D%2BK.E_%7Bf%7D)
![mgh+\dfrac{1}{2}mv_{i}^2=mgh+\dfrac{1}{2}mv_{f}^2](https://tex.z-dn.net/?f=mgh%2B%5Cdfrac%7B1%7D%7B2%7Dmv_%7Bi%7D%5E2%3Dmgh%2B%5Cdfrac%7B1%7D%7B2%7Dmv_%7Bf%7D%5E2)
Here, initial velocity and final potential energy is zero.
![mgh=\dfrac{1}{2}mv_{f}^2](https://tex.z-dn.net/?f=mgh%3D%5Cdfrac%7B1%7D%7B2%7Dmv_%7Bf%7D%5E2)
Put the value into the formula
![9.8\times1.5=\dfrac{1}{2}v_{f}^2](https://tex.z-dn.net/?f=9.8%5Ctimes1.5%3D%5Cdfrac%7B1%7D%7B2%7Dv_%7Bf%7D%5E2)
![v_{f}^2=2\times9.8\times1.5](https://tex.z-dn.net/?f=v_%7Bf%7D%5E2%3D2%5Ctimes9.8%5Ctimes1.5)
![v_{f}=\sqrt{2\times9.8\times1.5}](https://tex.z-dn.net/?f=v_%7Bf%7D%3D%5Csqrt%7B2%5Ctimes9.8%5Ctimes1.5%7D)
![v_{f}=5.42\ m/s](https://tex.z-dn.net/?f=v_%7Bf%7D%3D5.42%5C%20m%2Fs)
Hence, the greater speed of the ball is 5.42 m/s.
1) sound velocity reported by you : 292.39 m /s
2) time to travel 1620m at that velocity: t = d / v = 1620 m / 292.39 m/s = 5.54 s, since the moment the sound wave started.
3) You might wanted to tell the time since you watched the lightning.
Then you can calculate the time since the lighting was generated,1620 m away from you, until you saw it, using the speed of light:
speed of light = 3*10^8 m/s => t = 1620 m / (3*10^8m/s) =0.0000054 s
Then, this time is completely neglectible, and yet the answer is 5.54 s, as calculated in the step 2.