Equivalence Principle

The Equivalence Principle is a fundamental principle of physics which states that gravity operates as if the observer were in an upwardly accelerating frame of reference. Despite that it takes more force to move a more massive object through space (Newton's Second Law), in the influence of gravity all bodies fall without exhibition of inertial resistance. Likewise, experiments with light and atomic clocks have confirmed the nature of the Equivalence Principle.

=Description=

From Introduction to Cosmology by the 4th Cosmology School at Cracow, Portland, we see:



=Examples=

Monkey and the Hunter
https://web2.ph.utexas.edu/~gleeson/RelativityNotesChapter8.pdf

8.3.1 The Monkey and the Hunter



''Figure 8.3: Monkey and the Hunter A popular lecture demonstration is to fire a projectile at a hanging toy monkey. The monkey is released at the instant that the gun is fired.''

Science at the Amusement Park
https://web.archive.org/web/20200704180931/http://physics.gu.se/LISEBERG/callab.html

Carousel with Swings



=General Relativity and Accelerating Upwards=

The Equivalence Principle is a fundamental feature of General Relativity, which was interpreted to describe the surface of the Earth accelerating upwards through space time.

From Gravity: A Very Short Introduction by Cosmologist Timothy Clifton (bio), we read: