The bunchberry flower has the fastest-moving parts ever

QUESTION:

The bunchberry flower has the fastest-moving parts ever observed in a plant. Initially, the stamens are held by the petals in a bent position, storing elastic energy like a coiled spring. When the petals release, the tips of the stamen act like medieval catapults, flipping through a \(60^{\circ}\) angle in just \(0.30 \mathrm{~ms}\) to launch pollen from anther sacs at their ends. The human eye just sees a burst of pollen; only high-speed photography reveals the details. As FIGURE P12.66 shows, we can model the stamen tip as a \(1.0-\mathrm{mm}\)-long, \(10 \mu \mathrm{g}\) rigid rod with a \(10 \mu \mathrm{g}\) anther sac at the end. Although oversimplifying, we'll assume a constant angular acceleration.

a. How large is the "straightening torque"?

b. What is the speed of the anther sac as it releases its pollen?

Equation Transcription:

60o

Text Transcription:

60 degree

0.30 ms

1.0-mm-long, 10 mu g

10 mu g