# THE CONCEPT OF GRAVITY.

INTRODUCTION

The ability of an object to come down after they are thrown up depends on a factor that always acts to bring the object towards the centre of the earth. It always acts on an object that is above the earth surface. How high an object goes when thrown in the air is also dependent on this force. Our planet earth, and all other planets and heavenly bodies need the force of gravity to move at a fixed distance around the sun. How do the quantitative values of gravity affect lives on earth? This is a constant and stable force that acts on all objects whether you are aware or not. Aside from the numerous importance of gravity, it is also needed in the normal metabolism of the bodies of an organism. Continue to learn more about this incredible force.

### WHAT IS THE FORCE OF GRAVITY

From a physicist perspective, the force of gravity is the force that acts between any two masses in the entire universe. To the layman, the force of gravity is the force that acts on objects above the surface of the earth to give them a free fall ( the fall of an object under its mass and not any other force)

The value of the force gravity is not the same from one heavenly body to the other. Earth has a gravity of about 9.8 m/s2, that on the moon is 1.6 m/s2 and this figure differs as one move from one body to the other. Even on the same body, the value is not stable it slightly changes. On earth, the value of gravity is highest around the equator and decreases slightly as one move from the equator to the poles.

### FACTS ABOUT THE FORCE OF GRAVITY

1. It is by far the weakest naturally occurring force on earth. Even though this force is attractive, it does not seem to hold things together on earth. This is largely due to the mass, the action of this force is felt when the masses are extremely huge like the mass of the earth. This explains the reason why it is the force that keeps huge bodies in the solar system at a fixed distance from the sun.

2. Even though gravity and weight are closely related they are not the same. Weight is the force of gravity acting on the mass of an object. Mathematically,            W=m×g where W is the weight, m is the mass of the object and g is the force of gravity acting on the mass.

### RELATION BETWEEN THE UNIVERSAL FORCE OF GRAVITY (G) AND THE FORCE OF GRAVITY (g)

SIR ISSAC NEWTON worked on the force of attraction that exists between objects in the solar system. He came out with postulates that are known now as the NEWTONS LAW of universal gravitation. This law states that for every two masses ( body) in the universe there is a force of attraction that exists between them. This force is directly proportional to the product of the two masses and inversely proportional to the square of the distance that exists between them. This is mathematically represented by   F=GMm/R2  and g=GM/R2 where F is the force of attraction, G is the constant universal force of gravity, M is one on the masses ( the bigger one) and m is the smaller mass.

We have two masses because the law says that for any two masses in the universe there is a force of attraction between them. The value of G = 6.67×10-11 Nkg-2m2 and g= 9.8m/s2 approximately 10m/s2. With this, you can calculate the force of attraction that exists between any two masses. Maybe between you and your best friend or a lover. This is not a formula for affection calculation.

In short, if two bodies are extremely large the force is obtained by multiplying their masses over the square of the distance between them.

### THE EFFECT OR IMPORTANCE  OF GRAVITY ON THE EARTH'S SURFACE

Gravitational force acts on all objects on the earth regardless of the mass, so far as the mass of the object is >0, its effect is been felt.

Besides, it has a lot of importance in medicine, arts, geography and a lot more than we can imagine, even in indigestion, gravity plays a very important role to get food broken down into the simplest monomer. Let's discover more about the importance of gravity to man.

1) The force of gravity help things to move down when they are thrown up. It helps a ball thrown or played into the air to come down. Also, any other thing does the same when it is thrown up. If not, if you throw something up it will go and never came back. Think of how life will be under this condition.

2) It helps rain to fall: Without gravity, water will not fall. Gravity pulls objects towards the centre of the earth, so without gravity, the rain will "fall" above the sky.

3) Gravity together with peristaltic movement help to push food down the oesophagus into the stomach. Without gravity, food may not move down the stomach or will do so at a slower rate.

4) Gravity help us to urinate with little force from the abdominal walls. With little force from the abdomen, gravity gives a free fall that act on the mass of the urine.

5) It aids in the downward circulation of blood and water throughout the entire body. Aside from the heart that helps in circulation, gravity away helps move liquids and dissolved substances downward from the upper part of the body.

6) Gravity contribute to the value of atmospheric pressure on earth. Atmospheric pressure is a result of the force of gravity acting on a specific volume of a mass of air in the earth atmosphere. Without gravity, pressure, in general, won't exist because gravity has to act on the mass of the object. Also without gravitation, there will not be balance pressure in our body hence the blood and other body fluids will force their ways out leading to bleeding and eventual death.

### CONCLUSION

Gravity is a universal force of attraction that exists between any two masses on the surface. It helps pull objects toward the centre of the earth. Without gravity, nothing up comes down and whatsoever is thrown up goes and never comes down. Gravity acts on all bodies in the universe, with each heavenly body having its specific value. Even on the same body, the value is not constant it slightly varies. The universal gravitational constant act to keep the planets and other heavenly bodies at a fixed distance from the sun such that they orbit around the sun at regular intervals. For every vertical and horizontal motion of an object, that object has to move against gravity when it is moving up and against gravity when it is coming down.