Universal Gravitational Constant

In his law of gravitation, newton could not yet to determine the value of universal gravitation constant (G). but, the determination of it, first done by Henry Cavendish (1731 – 1810), a british physicist and chemist in 1798, after newton died.

The Formula of Gravitational Force

The gravitational acceleration experienced by every objects on the earth surface is approximately 9,8 m/s2.  the acceleration of the moon towards the earth can be calculated from the moon centripetal acceleration as follows.

The Definition Of Motion, Distance, and Displacement

Do you know what motion is?. In Physics, motion or often known as movement means a change in the location (position) of a body. In this case, motion is always observed and measured relatively to a given reference frame. for example, a car is said to be in motion, if the position changes relatively to a given reference frame, such as the ground, buildings, or trees. Meanwhile, a body is said to be at rest or motionless if the position is constant to a given reference frame.

The Invention of Gravitation Phenomenon

In the early of 1600's, a german mathematician and astronomer, Johanes kepler (1571 - 1630) was succeeded to analyze the astronomical data of the planets motion revolving the sun made by his teacher , Tycho Brahe. Based on result of analysis, Kepler proposed three laws about the planetary motion, those are as follows.