How Fast do the Objects Fall?

            When we know a ball up in the air, we observe that it gradually slows down, and the almost comes to a stand still, before it stars falling back to the ground. While it starts falling back to the ground. While falling down, it should be noted that the initial speed is low but gradually becomes high.

            The earth attracts all objects towards its centre with a force known as the force of gravity. The ball falls to the ground due to this force gravity. The force of gravity makes all falling objects acquire an acceleration, which is called the acceleration due to gravity. It is denoted by ‘g’.

            The acceleration due to gravity accelerates the ball roughly at 9.8 meters per second per second 32 feet per second. This means that each second the object would move 9.8 meters faster than the previous second. The speed of the ball at different intervals of time varies as follows.

            To begin with, the ball or a falling object is stationary or its speed is zero. At the end of 1 second, it travels 9.8 meters per second. At the end of 2 seconds, it moves 19.6 meters per second and at the end of 3 seconds, 29.4 meters per second and so on. In fact, every second, the object falls 9.8 meters per second faster than its speed in the previous second.

            Acceleration due to gravity is defined as the rate of change in velocity of a falling object with respect to time due to the force of gravity. Because it is measure of rate of change of velocity, it is expressed in meters per second, and is termed as meters per Second Square.

            The acceleration of body or object falling freely in vacuum varies slightly form place to place due to slight variation in the gravitational force of the earth, as the distance of the place form the center of the earth varies. In London, the value of ‘g’ is 9.807 meters per second per second, as North Pole 9.8 meters per second per second, and at the equator it is 9.79 meter per second. At sea level in Washington, it is 9.8008 meters per second per second.

            One of the important points to note about falling objects is that however heavy they might be, they all fall at the same rate. But, air resistance may retard the speed of falling objects. The famous scientist Galileo demonstrated this fact by dropping a heavy cannon ball and a light musket ball at the same time form the leaning tower of Pisa. Both the objects hit at the ground at the same time.

            Air resistance is the main reason why some objects fall slower than others. A feather, for example, floats slowly downwards because it faces more air resistance due to its relatively large surface area. A smooth, pointed bullet will fall faster than a feather because it experiences less air resistance. In vacuum both objects will fall at the same speed, as there would not be any air resistance.

The Earth’s Force of Gravity

What is the earth’s force of gravity?

            According to science, the earth attracts everything towards its centre. It is for this reason that fruits from trees or a ball thrown up into the air, all fall to the earth surface. This invisible force of attraction between the earth and any other body is called the force of gravity.

Gravitational pull keeps the moon revolving around the earth

            The centre of gravity of the earth lies in this center. Imagine what would happen if a hole is drilled in the earth form one side to the other, passing through its centre and a ball is dropped in this hole. The ball, in fact, will stop at the centre of the earth; it will not come out form the other side. The weight of a body will be more, if it is nearer the centre of the earth.

            Similarly, the weight will be less if the body is away from it. This is why a body weighs more at the poles than at the equator, since the poles are nearer to the centre than the equator.

            Not only the earth, but all other planets have this force of gravity. As a matter of fact, every body in this Universe attracts the other body with its force of gravitations, and it is this force that keeps all the planets and stars in their places in the sky. It is this gravitational pull that keeps the moon revolving around the earth, and the earth revolving around the sun.

            Naturally, the moon also attracts the earth; tides in the seas are mainly due to the gravitational pull of the moon.

            Till the end of the 15^th century, it was assumed that if two bodies were simultaneously dropped from the same height in vacuum, the heavier body would hit the ground first.

            But this assumption was found to be baseless. The famous scientist Galileo Galilei was the first to prove that irrespective of their masses, all the objects dropped simultaneously form the same point in vacuum will reach the ground at the same time. He dropped one ball weighing 100 pounds and another of just half pound at the same time from the learning tower of Pisa, and demonstrated in the presence of thousands of people that both the balls hit the ground at the same time.

            Subsequently, Newton propounded the law of gravitation. According to this law, the force of attraction between two bodies is directly proportional to the product of their masses ad inversely proportional to the square of distance between them. It follows form this that the force of attraction will be doubled if the mass of one of the two bodies is doubled.

            On the other hand, if the distance between them is doubled, the force will be reduced to one-fourth of the initial value. The velocity of a freely falling body towards the earth increases by 9.8 meters or 32 feet every second. This is called acceleration due to gravity.