Gravity Constant

Introduction to Gravity Constant

In order to understand Gravity constant one must first understand the concept of  Gravity.

Gravity is a force which tends to pull 2 or more bodies inwards or outwards. Gravity between Sun and Earth pulls the Earth towards the Sun but due to Earths own Gravitational Force it tends to push itself away from the Sun. This Push-Pull configuration results in a circular( or more precisely an elliptical ) motion of the Earth around the Sun. Same is applicable for the orbital motion of the Moon and the Earth.

I like to share this Formula for Gravity with you all through my article.

Gravity Constant : Satellites


However do not apply this theory for the satellites as the satellites operate on the Centripetal Force due their Orbiting Velocity around the Earth. The fundamental Difference between a Natural and an Artificial Satellite is that a Natural Satellite has its own Gravity where as an artificial Satellite doesn't have its own Gravity.

Now Newton studied this phenomenon and put forth the following discussion

Fα mM/R^2  i.e. The force between 2 bodies with masses m and M is directional proportional to their masses and inversely proportional to the square of the Distance R between them provided that the 2 masses are comparable to each other. But every proportionality should be substituted to equality. Hence this proportionality has  been converted to equality by introducing the Gravitational Constant also called the Big G , or the Newtons Constant.

Please express your views of this topic paper capacitor by commenting on blog

Gravity Constant : Calculation


It is very difficult to calculate the Gravitational constant. It was calculated on the basis of general cause and effect or push-pull behaviour of two bodies with significant masses. Its value has been calculated as  G=6.674 x 10^-11  Nm^2 /kg^2 which is also an approximate value.

It is very difficult to understand how we got this value as it took decades of research and experimentation to actually calculate its value. Gravity being the weakest force of the 3 Fundamental forces viz. Nuclear and Electromagnetic  wherein Nuclear Force is the Strongest..Also experimentation for calculations of the Gravitational constant was less physical and more mathematical as it is difficult to do actual experiment due to the Gravitational Pull of the earth.

Earth Attracts all bodies towards itself equally and hence everything whether big or small whether a small cricket ball or a large canon ball when thrown from the roof of a building falls down at the same "rate". Now when i say rate i mean acceleration. In introduced this topic as many students get confused between G and g. G is the Gravitational Constant as discussed with respect to the Force of Gravity. Where as g is the gravitational acceleration. its valued at approx 9.8m/s2 . However there is a numerical difference between these values at the Equator and at the Pole. its more at the Equator and lesser at the Poles. This id due to Oblong shape of the Earth.

When 2 bodies fall freely ( by freely means there is no other friction acting between then other than air which is almost negligible) they fall at the same rate because the force between the body and the Earth cannot be calculated as the Mass of  earth and that of any body on earth cannot be compared as Mass of Earth is an astronomical figure. Hence a free falling body falls with a velocity ( or acceleration) which is independent of its Mass. Of course a Feather would obviously fall at a slower rate as the friction of air acts on it. But if ti was to be dropped in vacuum then even a feather and a canon ball would fall from the same height and still reach the surface at the same time.