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1. ### Materials Question

You can find the mass density of the elements. You know Avogadro's Number. Use the density definition of mass over volume.
2. ### Lifting a mass problem

Draw a free body diagram, and solve the problem as you see the forces there (gravity, upward acceleration included). The acceleration would be modified.
3. ### One dimensional motion problem

Try using a positive value for g. Since when you ultimately calculate time, using a negative value would result in a negative value under the square root. Edit: Strike out what I said.
4. ### Estimate the density of the water

In 6 km, the change in pressure is significant. Here's something to get you started: Use the equation, B=dP/(d(rho)/rho) Manipulate and integrate, integral of (d(rho)/rho) = integral of (dP/B) That results in, ln(rho2/rho1)=exp((P2-P1)/B) Where you can say state 1 is the surface, and...
5. ### Chemical energy in the runner's body

That is a bad question. There are various forms of energy in that given situation. Both A and C are correct. There's heat transfer going on between the body and the ambient environment. However, there's electrical energy, kinetic energy, and chemical energy involved, as well. Muscular...
6. ### Shear Stress for Fluids

Thanks, but that's not what I'm looking for. I need to take the derivative of density with respect to y, and I need to use the shear stress to take the derivative. So I need to find a relationship between density and stress. I've tried using the Newtonian definition suggested by Stokes. I...
7. ### Shear Stress for Fluids

Homework Statement I have an empirically-derived equation for the shear stress of a fluid on a surface, given by the equation below. I am supposed to take the derivative of density with respect to distance, and I must use this equation to find an expression for density. Delta = Boundary...
8. ### Partial Density Homework: Integrate Momentum in Navier-Stokes

EDIT:I realize the images are big. I'm the process of scaling them down and re-uploading them. EDIT 2: Re-hosted and included updated images. I apologize for the bump, but can somebody please just go through this formulation and verify my work? It seems I am in fact eventually getting...
9. ### Efficiency of a Heat Engine

The contents inside the parentheses were correct before. You just had to change the exponent.
10. ### Partial Density Homework: Integrate Momentum in Navier-Stokes

Does the total density relation to the partial densities look correct? Intuitively, I was thinking total rho = rho_a + rho_v, but the equation, obviously doesn't support that.
11. ### Partial Density Homework: Integrate Momentum in Navier-Stokes

Homework Statement I am trying to integrate the momentum equation in the Navier-Stokes equations, and I need to make sure I have the density formulation correct. I'm unsure of my work because a lot of the terms in the end are canceling out. It's a two-phase mixture, so the sum of the partial...