Answer:
The initial velocity is 38.46 m/s.
Explanation:
The horizontal distance travel by the tennis ball = 13 m
The height at which the tennis ball dropped = 56 cm
Now calculate the initial speed of tennis ball.
The vertical velocity is zero.
Below is the calculation. Here, first convert centimetre into kilometre. So, height at which ball dropped is 0.56 km.




I think they can use more durable materials.
Usually, the forces that start the oscillation of buildings are the wind and microearthquakes.
The molecules of ice stick together in the process of cohesion. They are tightly packed so there isn't much room to move. Liquid water is a looser hold. The molecules can go past one another, and they will take the shape of whatever container they occupy. Water vapor is loosely contained, and it will will fill whatever container it is kept in, and it will take its shape, too.