The diameter of a locomotive wheel is 180 cm. In 2.5 minutes, the wheel has made 500 revolutions.

The diameter of a locomotive wheel is 180 cm. In 2.5 minutes, the wheel has made 500 revolutions. At what speed does the locomotive go?

Wheel diameter in meters: d = 180 cm = 0.18 m.
The path for one revolution of the wheel is equal to the circumference with a diameter of 0.18 m:
l = πd = 3.14 * 0.18 m = 0.565 m.
For 500 wheel revolutions, the path will be 500 times longer:
L = 0.565 m * 500 = 282.6 m.
Find the speed of the locomotive:
v = L / t = 282.6 m / 2.5 min = 113.04 m / min = (113.04 m / min) / (60 s / min) = 1.88 m / s.
The speed in meters per hour will be 60 times higher:
v = 113.04 m / min * 60 min / h = 6782.4 m / h ≈ 6.72 km / h.
Answer: 1.88 m / s ≈ 5.72 km / h.