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1. ### Work done as air expands in piston with spring

There's a problem in my thermo class that I think I have the right answer for, but the value I get doesn't seem to make sense. The problem reads: Warm air is contained in a piston-cyliner assembly oriented horizontally. The air cools slowly from an intial volume of .003 m^3 to a final volume...
2. ### Voltage dealing with two parallel plates

Hey guys. I'm having trouble analyzing a part of this problem. Two conducting, infinite sheets of charge (with thickness a) are fixed perpendicular to the x-axis as shown. The sheet from x = -2a cm to x = -a has a net charge per unit area -s and the sheet from x = +a to x = +2a has a net...
3. ### MAX/MINS with multivariables

Hey I was wondering if anyone can tell me if i am doing this right. f(x,y) = xy^2 ; R is the circular disk x^2+y^2<=3 So first i took the gradient, since I know a mix/min can exist if the gradient is equal to 0. Gradient of X= y^s Gradient of Y= 2xy So the point (0,0)...
4. ### Multivariable Tangent Lines

Hello, I was wondering if anyone can help me with this problem. Show that the line with equation 2ax+2by=a^2+b^2 is tangent to the circle with equation 4x^2+4y^2=a^2+b^2 If this is true, wouldn't the derivative of the circle equation be equal to the first equation? Would I just take...
5. ### Physics Problem; help me please

Well, you have a fairly basic question that comes from Netwon's second law of motion. By constant pull, the system has a constant force that is pulling the train along. This means that the system also has constant acceleration, which is given by Netwon's Laws. F = M A You can easily find...
6. ### Verifying Arc Length of Vector: <2e^t, e^-t, 2t>

Hello, I was wondering if someone could check and see that i did this problem right. You need to find the arc length of the vector from t=0 to 1: r= <2e^t,e^-t,2t> So first i took the derivative and got velocity. v=<2e^t,-e^-t,2> Next i used the formula for arc length. arc...
7. ### Max Curvature Points on y=ex & xy=1 - Help Needed!

ah , i think i got it. thanks, i was being stupid
8. ### Max Curvature Points on y=ex & xy=1 - Help Needed!

Hello, I just learned how to do these types of problems, but I'm having trouble. Can some one direct me through this problem? Find the point or points on the curve which the curvature is a maximum for a. y=ex b. xy=1 any help is greatly appreciated. I really am stuck here!
9. ### Aqueous Equilibria Help

I am stuck on this question...can anyone help? What is the pH after .10 mol NaCN is added to 100 mL of .050 M of HCN? (Ka=6.0x10^-19) I think I have to use the Henderson-Hasselbalch Equation. Is this the right way to take. And if so, how should I go about getting the ion concentration?
10. ### Energy Conservation Problem

ok thanks, I got it!
11. ### Energy Conservation Problem

would that be because there is no external torques acting on the system?
12. ### Energy Conservation Problem

Hey, I was wondering if anyone can help analyze this problem with me. Here is the question. A swing seat of mass M is connected to a fixed point P by a massless cord of length L. A child also of mass M sits on the seat and begins to sing with zero velocity at a position of which the cord...
13. ### Calculus II Problem: Dams and intergration by slicing

you also might be able to get the width of the dam by finding the arclength of the dam.
14. ### Calculus II Problem: Dams and intergration by slicing

i would find the volume of the damn using D=\frac{M}{V} I'm not sure on that. Once you get volume, do volume times density to get mass. Multiply mass by 9.8 m/s^2. I think that's it, but could be wrong.
15. ### Very Important Help Series

I believe there are 86 in the terms. you take 92-7+1=86
16. ### Can some 1 do this

It's really not necessary to use Simpson's Rule. Find an volume by cross-section. In order to do that, you need to develop an equation for the area, in this case a square. By the equations you gave, the length of one side of the square would be 4-[(x^2)-2]. Since the cross-sections are...
17. ### Another Electromagnetic Induction Question

I think I made a little progress. After drawing a force diagram, I think I could say that the magnetic force = the x component of the force of gravity(i split gravity into components rather than anything else). so then i said that: mg\sin{\theta}= \frac{B^2L^2v}{R} and then solved for v...

no problem.
19. ### Another Electromagnetic Induction Question

Again, this is a problem I got in my AP Physics Class can anyone help? I would really appreciate any help. My teacher didn't explain this concept too well. A metal bar with length L, mass m, and resistance R is placed on frictionless, metal rails that are inclined at an angle \theta...
20. ### Question on induced emf in a loop

Its ok, I found out how to do it. I forgot to mention that the Magnetic field has an initial magnitude of .750 T, and is decreasing at a rate of -.0350 T/S (there's your reason for changing magnetic flux) :approve:
21. ### Question on induced emf in a loop

Hey, I'm in a high school AP class and am stuck! Can anyone help me with this problem concerning induced emf? I would surely appreciate it. There is a loop of wire, shaped like a square. Each side is 20 cm long. There is a magnetic field directed into the page. What would be the way of...
22. ### Induced emf in a loop

Hey, I'm in a high school AP class and am stuck! Can anyone help me with this problem concerning induced emf? I would surely appreciate it. There is a loop of wire, shaped like a square. Each side is 20 cm long. There is a magnetic field directed into the page. What would be the way of...