Bouyant Force in a U Shaped Plastic Tube

Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
1 reply · 4K views
chillpenguin
Messages
13
Reaction score
0

Homework Statement


A plastic tube has a cross-sectional area of 5.00 cm^2. The tube is shaped sort of like a "U". The left arm is filled with water until the right arm of length 0.800 m is full of water. The right arm is then sealed with a cap that won't pop off until a force of 9.8 N is applied. What total height of water in the long arm (left arm) will put the seal on the verge of popping?


Homework Equations


F = ρ*V*g (Force = density * volume * acceleration from gravity)


The Attempt at a Solution


Trying to solve for the height h, I used the equation 9.8 N = (5.0 cm2)(1/10000 m2/cm2)(h)(1 kg/m3)(9.81 m/s2)
I'm using the value 1 kg/m3 as the density of water and 9.81 m/s2 as the acceleration due to gravity.

Isolating h, I got 1998 m, which seems way to large. I must be doing something wrong. The units work out though. I end up with meters. But the number seems way too large.
 
Physics news on Phys.org
Whoops I figured it out! I should be using a water density of 1000 kg/m^3!