Why does a heavier sphere fall faster in a liquid ?

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SUMMARY

The discussion centers on the dynamics of heavier spheres falling in a liquid, specifically addressing the forces at play: gravitational force (mg), buoyant force (F_b), and drag force (F_d). It is established that while gravitational force increases with mass, the acceleration of the sphere is influenced by the ratio of these forces. The conclusion drawn is that a heavier sphere, having the same volume as a lighter one, experiences a greater net force due to reduced drag force per unit mass, resulting in higher acceleration.

PREREQUISITES
  • Understanding of Newton's second law (F=ma)
  • Familiarity with the concepts of buoyant force and drag force
  • Basic knowledge of gravitational force and its constant nature
  • Concept of acceleration in fluid dynamics
NEXT STEPS
  • Study the principles of fluid dynamics and how they affect object motion
  • Learn about the equations governing buoyancy and drag force
  • Explore experiments demonstrating the effects of mass on acceleration in liquids
  • Investigate the relationship between density, volume, and mass in fluid contexts
USEFUL FOR

Students of physics, educators explaining fluid dynamics, and anyone interested in the mechanics of objects in liquids.

KingCrimson
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why do heavier balls fall faster in liquids ?, if F=mg-drag, a heavier ball would have greater mg, but the acceleration is given by F=ma, therefore mg-drag = ma, a = (mg-drag)/m.
I can't see how a heavier ball would fall faster.
 
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You've got ##a=g-F_D/m##. (minus is up here) If you increase mass, g is reduced more or less?
 
F=ma=mg-F_b-F_d where F_b is buoyant force and F_d is drag.

Then; a=g-F_b/m+F_d/m, so if you have two balls of same volume but different mass, the larger mass will have a higher acceleration.
 
Bandersnatch said:
You've got ##a=g-F_D/m##. (minus is up here) If you increase mass, g is reduced more or less?
g is constant, but Fd/m is reduced, I see it now :D thanks.
 

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