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Physics Buoyant Force

Cbarker1

Active member
Jan 8, 2013
255
Calculate the buoyant force (in N) on a 2.00 L helium balloon.

Work:

Upward is Buoyant
Downward is weight due to gravity

$$\Sigma F=0$$
$B-mg=0$
$B=mg$
$\rho=m/V$
$m=\rho*V$
$B=\rho_{fluid}*V_{fluid}*g$

I am stuck on $m=\rho*V$. Am I missing something?
 
Last edited by a moderator:

MarkFL

Administrator
Staff member
Feb 24, 2012
13,775
I would use:

[box=blue]
Archimedes' principle[hr][/hr]​
Any object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object.[/box]

So, you need only find the weight of 2.00 L of air. :)