# Search results

1. ### [PChem] Maxwell-Boltzmann Molecule Mean Speed

Thanks for following up :). Yes, I was confused at where the integral c=∫vf(v)dv was coming from (I don't like using random equations which I don't know where they came from) but I figured out it was pretty much just a definition.
2. ### [PChem] Maxwell-Boltzmann Molecule Mean Speed

Yes sorry, I see that my wording was ambiguous. I am having trouble seeing why integrating v*f(v) gives you an average.
3. ### [PChem] Maxwell-Boltzmann Molecule Mean Speed

Hi, I am having trouble with this concept... "A mean speed (c) is calculated by multiplying each speed by the fraction of molecules that have that speed, and then adding all the products together. When the speed varies over a continuous range, the sum is replaced by an integral. To employ...
4. ### [PChem] Van de Waals Partial Derivative

Thanks for both your help, guys. P.S. I found a free download for Maple from my university.
5. ### [PChem] Van de Waals Partial Derivative

Ray, I do! Thanks :) Is Maple a free program I can use to check my answers?
6. ### [PChem] Van de Waals Partial Derivative

Homework Statement Find (\frac{dV}{dp})_{n,T} for the Van de Waals gas law Homework Equations Van de Waals gas law: (\frac{p+an^2}{V^2})(V-nb)=nRT The Attempt at a Solution I just started doing problems like these so I would like to know if I am doing them right... What I did was I took...
7. ### Work w/ Pulleys

So only the parallel component is responsible for doing the work, correct?
8. ### Work w/ Pulleys

@Nathanael Ah, I think I was just making a stupid mistake. I was letting F = the force of gravity on the weight. Thanks for pointing that out.
9. ### Work w/ Pulleys

Homework Statement A force F is used to raise a 4-kg mass M from the ground to a height of 5 m. What is the work done by the force F? (Note: sin60 = 0.87; cos60 = 0.5. Ignore friction and the weights of the pulleys.) A) 50 J B) 100 J C) 174 J D) 200 J Please click here for picture. Homework...
10. ### Arithmetic Question Involving Quantum Physics

Homework Statement Two adjacent allowed energies of an electron in a one-dimensional box are 2.0 eV and 4.5 eV. What is the length of the box? Homework Equations E_n=\frac{h^2n^2}{8mL^2} The Attempt at a Solution My question is, since E_n and n^2 are both on separate sides of the equation...
11. ### Can someone explain Compton scattering?

Thanks a lot everyone :) I appreciate the input.
12. ### Can someone explain Compton scattering?

Thanks guys, So is absorption actually taking place here or is it a different type of interaction? I am getting mixed answers.
13. ### Can someone explain Compton scattering?

Hi, My textbook describes Compton scattering the following way: "...an x-ray photon...has a collision with a slow moving electron...the photon transfers energy and momentum to the electron [and recoils]..." Is it not true that by definition when a photon collides with a particle it...

Thanks :)
15. ### Power in an AC Circuit

So I can't use I^2R, because by definition the current would also be a different value for a new R? But we know the voltage will stay the same for a new R, so we can use V^2/R?
16. ### Power in an AC Circuit

Homework Statement The average power dissipated by a resistor is 4.0 W. What is the average power if the resistance R is doubled? Homework Equations P_{rms}=I_{rms}^2R=I_{rms}V_{rms}=\frac{V_{rms}^2}{R} The Attempt at a Solution I am told the answer is 2.0 W. But here's what I am confused...

Why would using degrees not give a unitless number?

Homework Statement The voltage across a 60μF capacitor is described by the equation vC =(18 V) cos(200t), where t is in seconds. What is the voltage across the capacitor at t =0.010 s? Homework Equations N/A The Attempt at a Solution When you use degrees the answer is 18V and...
19. ### Bulb Brightness

If I is the same for both resistors then according to P=I^2(R), R for the 60 W bulb must be higher. But I am confused because according to P = V^2/R the 60 W has a higher R...how do I know which equation to use?
20. ### Bulb Brightness

Homework Statement Normally, household lightbulbs are connected in parallel to a power supply. Suppose a 40 W and a 60 W lightbulb are, instead, connected in series. (see here) Which bulb is brighter? Homework Equations P_{resistor}=I\Delta V=I^2R =\frac{(\Delta V)^2}{R} The Attempt at a...
21. ### Electrical Resistance (Easy Question)

So if I'm not mistaken you can some them, \Sigma R = R_{muscle} + R_{fat} I think I can see why it would decrease now; just because more fat is being added doesn't make resistivity a bigger number. Fat was already present so the only number changing was A. Thanks guys.
22. ### Electrical Resistance (Easy Question)

Homework Statement A person gains weight by adding fat - and therefore adding girth - to his body and his limbs, with the amount of muscle remaining constant. How will this affect the electrical resistance of his limbs? a. the resistance will stay the same b. the resistance will...
23. ### Water Pressure

Oh you're right, sorry. Yeah they are circular pipes but I just wrote down the area incorrectly. I wrote down the pipes' radii for their area when I shouldn't wrote their radii^2*pi. Thanks for the help!
24. ### Water Pressure

Thanks And what mistake do you think I made for v_B? It worked out giving me the right answer :o.
25. ### Water Pressure

Hi, I am working on this water pressure problem, given: v_A = 2.0 \frac{m}{s} gauge pressure_A = 50 kPa the view is from above, no height changes find: gauge pressure @ B so, A_Av_A=2(A_Bv_B) 1.5*10^{-2}m^2(2.0\frac{m}{s})=2(5*10^{-3}m^2v_B) v_B=9.0\frac{m}{s} Bernoulli's equation (w/o...

Thank you :)
27. ### Heat Engine Question

Thanks :) Can you explain why putting all the energy from the hot reservoir to work would cause entropy of the system to decrease?
28. ### Heat Engine Question

Hi, I am trying to figure out heat engines. I don't understand why heat from a hot reservoir MUST exhaust heat into a cold reservoir. How does that satisfy the second law of thermodynamics? Why can't all energy from the hot reservoir be used to do work? Thanks
29. ### Slowing a Mass with a Spring Collision

Oh I see, I was thinking the spring was starting from it's maximum amplitude, but it's not; it's starting at its eq. point. Thanks :)
30. ### Slowing a Mass with a Spring Collision

Homework Statement A 1.5 kg mass slides across a horizontal, frictionless surface at a speed of 2.0 m/s until it collides with and sticks to the free end of a spring with spring constant 50 N/m. The spring's other end is anchored to the wall. How far has the spring compressed when the mass, at...