Why do astronauts float in the space station?

SCIENCE FACTS(Astronaut)

Weightlessness in an orbiting spacecraft is physically identical to free-fall.An object that rests on the ground is subject to a normal force exerted by the ground. The normal force acts only on the boundary of the object that is in contact with the ground. This force is transferred into the body.The force of gravity on every part of the body is balanced by stress forces acting on that part. A weightless astronaut feels weightless due to the absence of these stress forces.But actually they are not weightless.It is gravity that keeps the space station, the astronauts, and their equipment in orbit around the Earth.An object in orbit around the Earth is falling with sideways motion that is so rapid that as it falls, the Earth’s surface moves away at just the right rate that it falls around the Earth.This is exactly what the Moon is doing in its orbit around the Earth. It is falling, but moving sideways so rapidly so that instead of approaching the Earth’s surface, it remains at an approximately fixed distance.Inside the station,astronauts and their equipments float because they and their equipments are falling — falling around the Earth — along with everything inside their spacecraft.If we look at them from outside their spacecraft,we can see they are not floating and traveling in a circle around the Earth.But inside the space station,they appear to be floating,and they experience weightlessness.
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Sonic boom

Do you know what is sonic boom?

SCIENCE FACTS(Sonic boom)

When an object traveling through the air faster than the speed of sound,it creates such a strong shock wave that it is heard on ground as a sonic boom.Sonic booms produce abundant amounts of sound energy.Sonic boom is associated with shock wave.The shock wave starts at the nose of the aircraft and ends at the tail.When a supersonic aircraft creates a series of pressure waves in front of it and hitting the waves in front before they cannot get out of the way of each other,the successive waves are forced together or getting mixed up.This is how sonic boom is created. Longer aircraft spread out their booms more than smaller ones, which leads to a less powerful boom.

Roller coaster headache

What is the reason behind roller coaster headache?

SCIENCE FACTS(Roller-coaster)

A roller coaster is an amusement ride developed for amusement parks and modern theme parks.To make them safe for the riders engineers go to extreme length.But many people who ride roller coasters end up with a medical condition called roller coaster headache.This type of ride induces up and down,to and fro,and rotatory acceleration and this sudden change in acceleration can cause roller coaster headache.This sudden change in acceleration associated with roller coaster rides causes the tearing of bridging veins.This ruptures of blood vessels in the brain are mainly caused by the movement of brain relative to the skull.Engineers,designers,managers of amusement parks, and passengers on giant roller coasters should be aware of this risk."