A simple model of the core of a tornado is a right circular cylinder that rotates about its axis.

Question

A simple model of the core of a tornado is a right circular cylinder that rotates about its axis. If a tornado has a core diameter of 280 feet and maximum wind speed of 240 mi/hr (or 352 ft/sec) at the perimeter of the core, approximate the number of revolutions the core makes each minute. (Round your answer to one decimal place.)

 rev/min

Answer 1

We need to look at the circumference to determine how many revolutions it makes in a minute.

C = 2(π)r = (π)D = 280(π)

If the wind speed is 32 ft/sec, we need to determine how far it will go in 1 minute, or 60 seconds.

(32 ft/sec)(60 sec) = 1920 ft in 1 minute.

Since 280π feet is how far it travels in 1 rotation we have

(1920 ft)/280π feet = 2.18 revolutions, rounding to 1 decimal place, 2.2 revolutions in 1 minute