Tag: science & technology

For a simple pendulum, frequency f = (1/2π)√(g/L), meaning frequency decreases as length increases. It's inversely proportional to the square root of length, so 'inversely' is the correct choice among the given options. A longer pendulum swings fewer times per second.

The adult human skeleton consists of 206 bones, which decrease from approximately 270 bones at birth through fusion as we mature. This number includes both the axial skeleton (80 bones) and appendicular skeleton (126 bones).

Neptune was discovered in 1846 through mathematical predictions before being observed telescopically. Mercury, Jupiter, and Mars were all known to ancient civilizations as visible 'wandering stars' in the night sky.

Hurricanes have a distinctive calm center called the 'eye' surrounded by spiral rainbands with inward-flowing winds. Tornadoes have no calm eye, earthquakes are not storms, and thunderstorms lack this organized structure.

Nicolaus Copernicus formulated the heliocentric (sun-centered) model of the solar system in the 16th century, published in his work 'De revolutionibus orbium coelestium' (1543). This challenged the geocentric model. Option A (Copernicus) is correct. Plato predated this work; Galileo supported it later; Edwin Hubble worked on galaxies in the 20th century.

Red blood cells are scientifically called erythrocytes. Platelets are thrombocytes, leukocytes are white blood cells, and hemoglobin is the oxygen-carrying protein within red blood cells.

Newton's Second Law states that force equals mass times acceleration (F = ma). Force is the external agent that changes an object's motion. Velocity and speed describe motion but don't cause it, while mass is a property of the object.

Air contains approximately 21% oxygen, commonly rounded to 20% in general contexts. Nitrogen makes up about 78% of air, with trace gases making up the remaining 1%.