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# Sticks Kinematics

## Question

A yard stick was cut on 1 foot mark so that the other 2 footer stick cut can be placed on top of another yardstick to make it roll or pivot
on its ends and middle around (above and below) the yardstick clockwise.
While the 1 footer stick was placed on top of 2 footer stick to make it roll around it counterclockwise without touching the fixed yardstick.
Starting at position shown and same 1 RPM motion, how long will it take for the sticks to knock the ball down?

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## 4 answers to this question

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the 2 footer sticks out to the left of the yardstick every 2.5 revolutions (but its orientation is reversed every 2.5 revs. i.e. its left end is at the extreme left after 2,7,12,17,... revs. its right end is at the extreme left every 4.5,9.5,14.5,... revs). the 1 footer stretches out of the left edge of the 2 footer, every 3 revs (at 1,4,7,... revs) and stretches out of the right edge after 2.5,5.5,8.5,...revs.

Hence the ball is struck after 7 revs, or 7 minutes.

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Is the short stick (1ft) rotating around the long stick (2ft) with the 1RPM speed relative to the long stick or to the stationary yardstick?

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Relative to the long stick, i.e. when an a fly is on the long stick it would see both the short stick and the yard stick rotating at the same speed.

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If the rotating sticks moves in reverse instead of clockwise..then it would knock the ball in 1/2 minute

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