I have been wondering what is gravity for a long time now.
What causes things to fall to the ground?
Gravity is one of the fundamental forces of the universe that causes two particles to pull towards each other. It assists the formation of the universe and keeps the moon in orbit around the Earth.
It is not easy to answer what cause the forces as this is a question to be posed to the scientists. Newton and Einstein have their theories about gravity. It is therefore not easy for the man in the street to understand them. For those who are scientifically-minded, you can google for the exact explanation in the net or watch the videos here.
Initially Newton had also wondered (just like you) why the apple was attracted to the ground when one dropped onto his head!
Suffice to say, I understand gravity as the force that cause an object to fall to the earth at about 32 feet per second square (9.8 meters per second square)
The weight of an object changes depending on where you are. However, your mass remains constant. If you are on the moon, the gravity is 1/6 that of the earth. So if you weigh 60 kgs on earth, you would be only 10 kgs on the moon!
From a pilot's point of view, gravity is the force that pulls a plane back to Earth. So, in order for a plane to rise or climb, the lift force on the wings must be stronger than the pull of gravity. For instance, if a plane weighs 100,000 kgs then the lift must be 100,001 kgs or more in order for the plane to climb.
Fighter pilots used to refer to gravity as ‘G’ force. A pilot that weighs 80 kgs (1 G) on the ground would experience, in some flight manoeuvres of up to 5 G's. That is 400 kgs (5 x80) without getting blackout (or loss of consciousness) because they are wearing anti-G suits.
So what is gravity force? It is something abstract - much like trying to explain what cause a magnetic force. Some physicists think gravity is caused by gravitons, but they are still unsure.
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