Of course they are needed because without them the society wouldn’t be as nice as it is right now and plus there would be no more buildings ! :)
Answer:
The pressure reduces to 2.588 bars.
Explanation:
According to Bernoulli's theorem for ideal flow we have

Since the losses are neglected thus applying this theorm between upper and lower porion we have

Now by continuity equation we have

Applying the values in the Bernoulli's equation we get

Answer:
i don't know if this help tell me if i am wrong
Explanation:
Gravity is the force that pulls all elements of matter together. Matter refers to things you can physically touch. The more matter there is, the greater the amount of gravity or force. This means that the Earth or other planets have a great deal of pull and that everything on Earth is pulled back to Earth.
Some examples of the force of gravity include:
The force that holds the gases in the sun.
The force that causes a ball you throw in the air to come down again.
The force that causes a car to coast downhill even when you aren't stepping on the gas.
The force that causes a glass you drop to fall to the floor.