Elif and Fergus ride the same merry-go-round. Elif sits near the rim, and Fergus sits near the center post. Every turn takes the two of them exactly the same time.
Who moves at the greater speed?
The two riders share a period: one full turn takes each of them the same time.
They do not share a path. Elif's circle is bigger than Fergus's circle.
A bigger circle is a longer trip. The distance around a circle of radius r is the circumference, 2πr.
Speed is distance traveled divided by the time taken.
Each turn, Elif covers more distance than Fergus in the same time. So Elif moves at the greater speed.
The two riders do sweep the same angle each second. Matching angles do not make matching speeds.
Speed follows the distance covered, and the rider on the bigger circle covers more of it.
Two raindrops cling to a spinning umbrella, one near the tip of a rib and one near the center pole. The umbrella turns steadily. Which drop moves at the greater speed?
A revolving door turns steadily. A handle near the outer edge moves faster than a hinge point near the center shaft. Why is the handle faster?
Two carousel horses turn together, one 2.0 m from the center and one 5.0 m from the center. Which horse moves faster?
The horses share a period: they turn together.
The outer horse's circle has radius 5.0 m, so each turn it covers a circumference of 2π × 5.0 m.
The inner horse's circle has radius 2.0 m, so each turn it covers only 2π × 2.0 m.
More distance in the same time is a greater speed.
The horse 5.0 m from the center moves faster.
A vinyl record spins steadily. One speck of dust sits near the rim, and another sits near the middle. Which speck moves faster?
The record is one stiff disc, so both specks share its period.
The rim speck rides the bigger circle, so each turn it covers the longer circumference.
More distance in the same time is a greater speed.
The speck near the rim moves faster.
Henrik says: 'Two beads taped to one fan blade take the same time per turn, but the bead farther from the hub moves faster.' Is Henrik correct?
A clock's minute hand turns steadily. One point sits at the hand's tip, and another sits halfway between the center and the tip. Which point moves at the greater speed?
A rotating restaurant floor turns steadily. Golda's table near the window edge moves faster than a table near the central core. Why is Golda's table faster?
Two children sit on a playground spinner, one near the rim and one near the middle. The spinner turns steadily. Which statement is correct?