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F = ma (11–17)
Dimensional Analysis
FMA-2020A-16 · 2020A F = ma (AAPT)

2020 F = ma Exam A — Question 16

Liquid droplets store a given amount of potential energy per unit surface area, due to their surface tension. When two identical, nearly spherical liquid droplets coalesce on a certain type of surface, part of this energy can be converted into upward kinetic energy, causing the coalesced droplet to jump. Assuming the conversion is 100% efficient, how does the maximum height h depend on the radius r of the initial droplets?
Source: Question 16, 2020 F = ma Exam A, © 2020 American Association of Physics Teachers (AAPT) and the U.S. Physics Team. Adapted by PhysicsTrainer: reformatted into a separate question and answer choices for online multiple-choice practice; any shared setup from nearby questions is repeated here. Not affiliated with or endorsed by AAPT or the U.S. Physics Team.