pendulum measurements
51Mass — This article is about the scientific concept. For the substance of which all physical objects consist, see Matter. For other uses, see Mass (disambiguation). Classical mechanics …
52Tropical year — A tropical year (also known as a solar year), for general purposes, is the length of time that the Sun takes to return to the same position in the cycle of seasons, as seen from Earth; for example, the time from vernal equinox to vernal equinox,… …
53Devil sticks — Children learning the pendulum The manipulation of devil sticks (also devilsticks, devil stixx, flower sticks, devil sticks, rhythm sticks, gravity sticks, or juggling sticks) is a form of gyroscopic juggling or equilibristics, and is generally… …
54Attitude dynamics and control — The attitude of a body is its orientation as perceived in a certain frame of reference; providing a vector along which a spacecraft is pointing is a description of its attitude. Dynamics is the term for the modeling of changing conditions, due to …
55List of Chinese inventions — A bronze Chinese crossbow mechanism with a buttplate (the wooden components have …
56Foot (unit) — 1 foot = SI units 0.3048 m 304.8 mm US customary / Imperial units 0.333 yd 12 in A foot (plural: feet; abbreviation or symbol: ft or ′ (the prime symbol) is a unit of length in a number of different systems including …
57Ole Rømer — Rømer redirects here. For other uses, see Romer (disambiguation). Ole Rømer Ole Rømer, portrait by Jacob Coning from c. 1700 …
58parallax — parallactic /par euh lak tik/, adj. parallactically, adv. /par euh laks /, n. 1. the apparent displacement of an observed object due to a change in the position of the observer. 2. Astron. the apparent angular displacement of a celestial body due …
59John Harrison — Infobox Scientist name = John Harrison |300px image width = 260px caption = P.L. Tassaert s half tone print of Thomas King s original 1767 portrait of John Harrison, located at the Science and Society Picture Library, London birth date = birth… …
60Astronomical clock — An astronomical clock is a clock with special mechanisms and dials to display astronomical information, such as the relative positions of the sun, moon, zodiacal constellations, and sometimes major planets. DefinitionThe term is loosely used to… …
