Chapter 12, Problem 85EAP

1. sThe 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 angle in just 0.30 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 CP12.85 shows, we can model the stamen tip as a 10-mm-long, 10 µg rigid rod with a anther sac at the end. Although oversimplifying, we’ll assume a constant angular acceleration.
2. How large is the “straightening torque”?
3. What is the speed of the anther sac as it releases its pollen?