Chapter 3, Problem 3.83PP

BIO BALLISTIC SEED DISPERSAL. Some plants disperse their seeds when the fruit splits and contracts, propelling the seeds through the air. The trajectory of these seeds can be determined with a high-speed camera. In an experiment on one type of plant, seeds are projected at 20 cm above ground level with initial speeds between 2.3 m/s and 4.6 m/s. The launch angle is measured from the horizontal, with +90° corresponding to an initial velocity straight up and −90° straight down.

3.83    About how long does it take a seed launched at 90° at the highest possible initial speed to reach its maximum height? Ignore air resistance, (a) 0.23 s; (b) 0.47 s; (c) 1.0 s; (d) 2.3 s.