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Thu 19 Dec, 2013 12:01 pm
A prison guard tower sits 100 yards from a jail and shines a light across the jail yard at 5 revolutions each minute. This is equivalent to 12 pi radians/minute. How quickly is the spot of light moving across the jail yard when it is 50 yards from the point on the jail yard which is nearest the guard tower?
Equivalent to 10 pi radians/minute.
@R12rohrbacher,
No Calculus is needed--the angular rotation of the light is a constant 12pi/min.
If the tower (circle) is 100 yards from the wall (line). The closest distance is a point on a line perpendicular at 100 yds. Half that is on this perpendicular line at 50 yards. The light still is panning at 12pi/min.
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