1. ### B How things Float

Imagine a container containing water up to 100cm of its height then I dip a cube of plastic in the water on depth of 75cm. We all know it will float because of its less density, but if we go with Pascal Law, The pressure/force applied by the water above the cube is more than than the buoyant...
2. ### I Is there an absolute density?

This is kind of a random question. Is there a point that a substance density will max out? Or in other words that it cannot be compressed any further no matter the energy you add to the system?
3. ### Chemical Polymer Separation (PLA, ABS, HIPS, and PETG)

Good day all! I've got a granular mixture of PLA, ABS, HIPS, and PETG with a particle size of about a quarter inch, and I'm trying to isolate each polymer from the mix. PLA and PETG have densities of about 1.27g/ml, and ABS and HIPS have densities of around 1.06g/ml. I think a weighted solution...
4. ### Finding the density

A overflow container that its overflow level is $100$ $cm^3$ has $80$ $cm^3$ water. When a stone that is $120$ $g$ is being dropped into the overflow container, the water increases $10$ $cm^3$. How to find the density? I currently don't have any idea about it.
5. ### I Understanding Gauss' law: diff b/w E and D flux?

I noticed the other day something odd in how we use Electric and Magnetic flux. The definitions I refer to are magnetic flux density (B), magnetic flux intensity (H), electric displacement field (D) or Electric field density (D) and electric field (E): B = μH ΦB = B*Area & D = εE ΦE = E*Area...
6. M

### Finding population density with double integrals

Homework Statement A city surrounds a bay as shown in Figure 1. The population density of the city (in thousands of people per square km) is f(r, θ), where r and θ are polar coordinates and distances are in km. (a) Set up an iterated integral in polar coordinates to find the total population...
7. ### I Electric field integral: Convergence where ρ is nonzero

Hi. I know how to use Gauss' Law to find the electric field in- and outside a homogeneously charged sphere. But say I wanted to compute this directly via integration, how would I evaluate the integral...
8. H

### Fluid Statics- u-tube displacement

Homework Statement A uniform U-tube is partially filled with water (ρH20 = 1000 kg/m3). Oil, of density 750 kg/m3, is poured into the right arm until the water level in the left arm rises 30 mm. The length of the oil column is then: (Answer: 40mm) Homework Equations P = pgh Pressure = density...
9. M

### B An infinitly dense human body

Hello, I've been watching too much anime. I know that isn't the best way to ask a question scientific in nature, but visualizing bizarre situations is one of the best ways to come up with interesting questions. Anyways, in order to break a rock by compressing it with your hands, you would need...
10. N

### Pressure at the center of an accelerating sphere

Homework Statement Consider a glass sphere completely filled with water except for a small air bubble at 1 atmosphere. The sphere is accelerating to the right. What is the pressure at the center of the sphere? Let Pe = Atmospheric pressure r = radius of sphere pw = density of water a =...
11. ### B What property of a fluid determinates rising and sinking Velocities

If we have a bottle with a fluid A of X density, and in the bottom of this bottle it magically spawns the same amount of fluid B with X/2 density, fluid B should rise in fluid A until they both change positions and fluid B floats in A. Wich property of the fluids are the ones that determinates...
12. M

### Solids with different sound velocity at diffrent tempratures

i work on phononic crystals and i want to find solids with diffrent sound velocities and mass density in diffrent temprature i can just find BST but i need more matherials please help me my friends best regards
13. ### Is diborane lighter or heavier than air?

Hi, I have been reading about diborane (B2H6, a gas at standard conditions) and while the sources provide different density values (!), as in 1.2475 g/L at standard conditions, or 1.18 g/L at 15ºC and 1.216 g/L at 25ºC (sounds crazy?), all of them are lower than dry or moist air at the same...
14. ### B How can Greenland lose 269b tons/year and loose only 269km3?

The density of ice is 920 kg/m3. Now let's calculate. m = 269 000 000 000 000 kg p = 920 kg/m3 ----------------------------- v=? V=m/p V=269 000 000 000 000 kg / 920 kg/m3 V = 292 391 304 347 m3 = 292 391 304.347 km3 v > 269 km3 *NOTE* I made a mistake in the title. I meant to write 269 km3...
15. ### Radius of a raindrop

Homework Statement Using the viscosity of air as 1.8x10-5Pa s, and the density of water as 1x103kg m-3, find the radius of a raindrop travelling at a terminal velocity of 7.05ms-1. Assume Stokes law can be used. The problem is finding the density of air, I could use F = 6rvπη but I don't know...
16. ### By how much is each post compressed?

Homework Statement A large 30000 L aquarium is supported by four wood posts at the corners. Each post has a square 6.00 cm x 6.00 cm cross section and is 90.0 cm tall. Take Y=10^10 for wood Homework Equations ΔL = FL/AY F = ma ρ = m/V The Attempt at a Solution So the total area is 0.06 * 0.06...
17. ### Buoyant Force Question

Homework Statement - [/B] What is the buoyant force that acts on a fully submerged 1-L bottle of water? What is the buoyant force that acts on it if it is full of air, not water, but is still fully submerged? Assume you'd have to hold it under water. Homework Equations - [/B]Fb= V x D x G...
18. ### B Finding impact depth

I'm trying to find the impact or penetration depth of a projectile in the (reasonably) most realistic way possible. I assume this has many factors including velocity, the densities of both materials, shapes of both materials, the medium of which the projectile travels through, gravity, etc...
19. ### I Humid Air Density Forumulas

I'm trying to compile a complete list of available humid air density formulas that work with air pressure, temperature and dew point (or RH). If you know any, please advise. Thanks, Robert
20. ### Find the density of this gas

Homework Statement In temperature 273 kelvin and pressure 1.013*10^5 Pa, the density of nitrogen is 1,25 kg/m3. Find the density of this gas in temperature 330 kelvin and pressure 1.40*10^5 Pa. T1=273 K; p1=1.013*10^5Pa; d1=1.25 kg/m3 T2=330 K; p2 =1.4*10^5 Pa. d2=? Homework Equations...
21. ### I Special Relativity's effect on density

Special relativity states that according to an observer at rest, a measuring stick on a moving platform will appear shorter. Would this observer still see the measuring stick as comprising of the same amount of atoms as the observer who is at rest with respect to the measuring stick? If this is...
22. ### 1D Wave equation problem

Homework Statement Hello- I'm having trouble understanding a problem: Consider a sealed 1D pipe of length L. At t=0, v=0 everywhere and the pressure is given by: P=P_0 +δP and δP = (p-bar)x/L P_0 and (p-bar) are both constants. and I'm supposed to find density (ϱ) as a function of x and t...
23. ### What would happen to the ball?

Homework Statement Assume that the beaker is half filled with Hg, the steel ball being lighter will float in it half-submerged. Now we pour water into the beaker, so that the beaker is completely filled with water on top, Hg in the bottom and steel ball floating between them. Now my question...
24. ### Finding the gauge pressure at the bottom of a barrel

Homework Statement A barrel contains 0.130-m layer of oil floating on water that is 0.290 m deep. The density of the oil is 610 kg/m3 What is the gauge pressure at the bottom of the barrel? Homework Equations P [/B]= ρ(g)(h) The Attempt at a Solution I found the pressure of the oil which...
25. ### Can a balance give accurate reading if measured on the moon?

Question: On the Moon, the force of gravity on an object is only about one-sixth of its value on Earth. Decide whether each of the following would give an accurate measurement of the mass if used on the Moon a) A beam balance like the one in the diagram at the top of the page b) A balance...
26. ### Coaxial metal cylinders

Homework Statement [/B] Two long, coaxial metal cylinders are separated by a material of conductivity sigma and dielectric constant epsilon. The radius of the inner cylinder is a, the radius of outer cylinder is b, and the length of both is L. Suppose that the inner conductor is held at a...
27. ### Calculating the resultant electric field

Homework Statement In the picture below it is asked that i calculate the resultant electric field if the linear charge density is known. Calculate the resultant electric field of a charged semicircle wire (positioned as in the picture) at some point M on the Z axis if the linear charge density...
28. ### B What are the different kinds of charge density?

At this point I was given rho, sigma and landa to hold value of these three different kinds of density ρ = Charge/Volume -------------- Volume Density σ = Charge/Area ----------------- Area Density λ = Charge/Length ---------------- Length Density How do I know which type of density to use over...
29. ### Mass of Ceramic on a Wire

Homework Statement A metal wire is given a ceramic coating to protect it against heat. The machine that applies the coating does not do so very uniformly. The wire is in the shape of the curve The density of the ceramic on the wire is Use a line integral to calculate the mass of the...
30. ### Floating block with objects that are thrown in a liquid

Homework Statement I'm confused about the following kind of situation. Consider a block of density ##\rho_b##, mass ##M_b## and section ##S_b## that floats on a liquid of density ##\rho_l##, in a tank of section ##\mathcal{S}##. On the block there are some objects (all equal), of density...