Two spheres falling through water..terminal velocity?

In summary, the conversation discusses the terminal velocity of a glass sphere and a wooden sphere falling and rising through water. The glass sphere has a diameter of 1.75 cm and density of 2.5 g/cm^3, while the wooden sphere has the same diameter but a density of 0.85 g/cm^3. The terminal velocity for the glass sphere falling is given as 0.3 m/s. The problem is to determine the terminal velocity for the wooden sphere rising. The conversation also mentions converting units and needing a hint on which equation to use. The answer to the problem is determined to be 3 cm/s upward direction.
  • #1
imatreyu
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0

Homework Statement



A glass sphere of diameter 1.75 cm and density 2.5 g/cm^3 falls through water with a terminal velocity of 0.3m/s. A wooden sphere of the same diameter and density 0.85 g/cm^3 is released from the bottom of a tank of water. Determine the terminal velocity with which the wooden sphere rises.

Homework Equations


I have no idea where to start! Could someone point me in the right direction?


The Attempt at a Solution



I converted everything so that all units are in kg or m . . .

But now I have no idea what equation to use, etc. . . Just a hint. . would be nice.

Thank you, in advance!
 
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  • #2
answer is 3cm/s upward direction
 

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  • #3
Oh. . .Wow, thank you.
 

1. What is terminal velocity?

Terminal velocity is the maximum speed that an object can reach when falling through a fluid, such as air or water. It occurs when the gravitational force pulling the object down is equal to the resistance force of the fluid pushing against it.

2. How does the size and shape of the object affect its terminal velocity?

The size and shape of an object can affect its terminal velocity because it determines the amount of surface area that the fluid can push against. Objects with a larger surface area, such as a flat sheet, will experience more resistance and reach a lower terminal velocity compared to smaller, more streamlined objects.

3. Does the density of the object or fluid affect terminal velocity?

Yes, both the density of the object and the fluid will affect the terminal velocity. Objects with a higher density will experience more gravitational force and reach a higher terminal velocity. Similarly, fluids with a higher density will provide more resistance, resulting in a lower terminal velocity for the falling object.

4. Can the viscosity of the fluid affect the terminal velocity?

Yes, viscosity, or the thickness of the fluid, can affect the terminal velocity. Higher viscosity fluids, such as honey, will provide more resistance and result in a lower terminal velocity for the falling object. Lower viscosity fluids, such as air, will have less resistance and allow the object to reach a higher terminal velocity.

5. How do other factors, such as temperature and altitude, impact terminal velocity?

Temperature and altitude can impact terminal velocity in several ways. As temperature increases, the viscosity of the fluid decreases, allowing the object to reach a higher terminal velocity. Similarly, at higher altitudes, the air density decreases, resulting in less resistance and a higher terminal velocity for the falling object.

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