Two spheres of the same size but different densities fall through the same viscous liquid. The denser one has
Correct answer: C. a higher terminal velocity
- A. the same terminal velocity
- B. a lower terminal velocity
- C. a higher terminal velocity
- D. no terminal velocity
Explanation
Terminal velocity depends on the difference between the density of the sphere and that of the fluid, so a denser sphere needs a larger drag force to balance its greater weight and must therefore fall faster to generate it. Radius and viscosity being equal, density is the only variable left. If the sphere were less dense than the liquid it would rise instead.
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About Terminal Velocity
Terminal velocity is the constant speed reached when gravitational force is balanced by fluid resistance. The topic covers drag, buoyant force, the conditions for zero acceleration, and how viscosity, object size, shape and density affect the limiting speed, with a distinction between free fall before and after terminal velocity.
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