# How far does a person sitting by the window move in 100 minutes if the radius of the restaurant is 21 meters?

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- NCSLv 71 month ago
There are lots of rotating restaurants out there. Assuming yours rotates once every hour (like, say in Seattle and Niagara Falls), then

s = r*Θ = r*ω*t = r*(2π/T)*t = 21m * (2π/60 min) * 100min

s = 220 m ◄

is the DISTANCE moved.

If your restaurant has a different period T, then plug that value in and recalculate.

Now that's different from "how far are they from where they started" (the DISPLACEMENT). They've gone around 120º short of a second complete circle.

c² = 21² + 21² - 2*21*21*cos120º = 1323 m²

c = 36 m (straight line) from where they started.

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