What is the mass density of a submerged cylinder?

In summary, the conversation discusses how to find the mass density of a floating cylinder by using the equation for buoyancy and the ratio of the density of the object to the density of the fluid. The conversation also mentions different approaches to solving the problem, such as equating the volume of water needed to equal the mass of the cylinder or using the equation F = rho * V * g. Ultimately, the solution is found by canceling out the unknown radius and solving for the density of the object.
  • #1
cyclemun
9
0

Homework Statement


A 6.40 cm-tall cylinder floats in water with its axis perpendicular to the surface. The length of the cylinder above water is 1.00cm.

Homework Equations


What is the cylinder's mass density?


The Attempt at a Solution


Well, I am confused because I can use the equation for buoyancy to find the mass of the cylinder, but I don't know how to find its volume.
 
Physics news on Phys.org
  • #2
You don't need the radius of the cylinder to find the volume. The question only asks for its density. Just write out the equation using 'r' to denote the unknown radius and something will cancel out.
 
  • #3
so would i use the forumula F = rho* V * g?
 
  • #4
The way I would go about doing this problem--I don't know if it's the best way--is to say the cylinder has a mass m, then figure out the volume of water needed to equal this mass. You can then equate this to a formula for mass of the cylinder.
 
  • #5
cyclemun said:
so would i use the forumula F = rho* V * g?
You still need to break V up in terms of r and h.
 
  • #6
Weight of the cylinder= Area*6.4 cm*density*g
Weight of the displaced water= Area*5.4*1000*g
Now find the density.
 
  • #7
I have the same problem just different numbers... I am confused on what to do. F=rho*v*g
then after you cancel out you get
F=mhg right? is that the force on the bottom?
 
  • #8
For a floating object the fraction of the volume of a floating object that is below the fluid surface is equal to the ratio of the density of the object to the density of the fluid:

V-f/V-o=rho-o/rho-f as has been noted, the radius cancels, you know rho-f, you can solve directly for rho of the object.
 

What is a cylinder submerged in water?

A cylinder submerged in water is a cylindrical object that is completely or partially immersed in water.

What happens to the water level when a cylinder is submerged in water?

The water level will rise when a cylinder is submerged in water because the volume of the cylinder displaces the same volume of water.

What is the relationship between the weight of a submerged cylinder and the weight of the displaced water?

The weight of a submerged cylinder is equal to the weight of the displaced water. This is known as Archimedes' principle.

How does the shape of a submerged cylinder affect the buoyant force?

The shape of a submerged cylinder does not affect the buoyant force. As long as the volume of the cylinder is the same, the buoyant force will remain constant.

What other factors can affect the buoyant force on a submerged cylinder?

The buoyant force on a submerged cylinder can also be affected by the density of the cylinder and the density of the water it is submerged in.

Similar threads

  • Introductory Physics Homework Help
Replies
25
Views
3K
  • Introductory Physics Homework Help
Replies
21
Views
1K
Replies
39
Views
1K
  • Introductory Physics Homework Help
Replies
1
Views
1K
  • Introductory Physics Homework Help
Replies
8
Views
663
Replies
13
Views
818
  • Introductory Physics Homework Help
Replies
18
Views
1K
  • Introductory Physics Homework Help
Replies
7
Views
1K
  • Introductory Physics Homework Help
3
Replies
97
Views
11K
  • Introductory Physics Homework Help
Replies
16
Views
1K
Back
Top