BLOG DE ALFABETIZACIÓN MATEMÁTICA "DORA-SHEIKHA MAHRA BINT MOHAMMED BIN RASHID AL MAKTOUM"

BLOG DE ALFABETIZACIÓN MATEMÁTICA “DORA - SHEIKHA MAHRA BINT MOHAMMED BIN RASHID AL MAKTOUM”. Educación científica trilingüe.

"DORA - SHEIKHA MAHRA BINT MOHAMMED BIN RASHID AL MAKTOUM" MATHEMATICAL LITERACY BLOG. Trilingual science education.

"DORA - SHEIKHA MAHRA BINT MOHAMMED BIN RASHID AL MAKTOUM"  BLOG DE LITTÉRATIE MATHÉMATIQUE. Enseignement trilingue des sciences.

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CAPÍTULO VIII: "MOVIMIENTO CIRCULAR, LOS PLANETAS Y LA GRAVEDAD"

CHAPTER VIII: "CIRCULAR MOTION, PLANETS AND GRAVITY"

CHAPITRE VIII : « MOUVEMENT CIRCULAIRE, PLANÈTES ET GRAVITÉ »

 

Linear speed, which we simply called speed in previous chapters, is the distance traveled per unit of time. A point on the outside edge of a merry-go-round or turntable travels a greater distance in one complete rotation than a point nearer the center. Traveling a greater distance in the same time means a greater speed. Linear speed is greater on the outer edge of a rotating object than it is closer to the axis. The linear speed of something moving along a circular path can be called tangential speed because the direction of motion is tangent to the circumference of the circle. For circular motion, we can use the terms linear speed and tangential speed interchangeably. Units of linear or tangential speed are usually m/s or km/h.

Rotational speed (sometimes called angular speed) involves the number of rotations or revolutions per unit of time. All parts of the rigid merry-go-round and turntable turn about the axis of rotation in the same amount of time. Thus, all parts share the same rate of rotation, or the same number of rotations or revolutions per unit of time. It is common to express rotational rates in revolutions per minute (RPM).For example, most phonograph turntables, which were common several years ago, rotate at 33* RPM. A ladybug sitting anywhere on the surface of the turntable revolves at 33* RPM.

Physics types usually describe rotational speed, w, in terms of the number of "radians" turned in a unit of time. There are a little more than 6 radians in a full rotation (27T radians, to be exact). When a direction is assigned to rotational speed, we call it rotational velocity (often called angular velocity). Rotational velocity is a vector whose magnitude is the rotational speed. By convention, the rotational velocity vector lies along the axis of rotation.

Tangential speed and rotational speed are related. Have you ever ridden on a big, round, rotating platform in an amusement park? The faster it turns, the faster your tangential speed. This makes sense; the greater the RPMs, the faster your speed in meters per second. We say that tangential speed is directly proportional to rotational speed at any fixed distance from the axis of rotation.