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1. ### Research assistant wages?

Ya, Norman. I do need to incorporate fringe benefits as well. If you happen to have your proposals easily at hand then that would be great. If not, don't worry about it. The PhD is not necessarily in physics. In this particular case, we have a Biochemist, a Physicist, and a Materials...
2. ### Research assistant wages?

So I have to put together a mock budget for a funding proposal. I am unsure, however, how much I need to pay the research assistants I will have working on the project. I also don't have a good idea of how much a professional with a PhD or master's would be paid to work on a project. I...
3. ### Best Guitarist Ever

Marty Friedman and Jason Becker. Just listen to this song Concerto.
4. ### Undergrad Research: Overcome Intimidation & Enjoy

Doe anyone have any actual research experience? Like the guys above said, what can you actually do with only a couple years of undergraduate education?
5. ### Undergrad Research: Overcome Intimidation & Enjoy

Hi guys, This summer I am looking to get involved in research at my university. I am eager to go and meet with a professor to see if I can hold a position for him, but I am very intimidated and I sometimes feel like I don't know enough to contribute to a research team. I have been told...
6. ### Calculating Moment of Inertia Tensor for Rod Along x Axis

Okay, so I think I figured out my problem. I was doing something wrong with the component form. Here is what I got for my inertia tensor: I_11 = 0 I_22 = (1/3)ml^2 I_33 = (1/3)ml^2 I_12 = I_21 = 0 I_13 = I_31 = 0 I_23 = I_32 = 0 So it looks something like this: [..0...0.....0...]...
7. ### Calculating Moment of Inertia Tensor for Rod Along x Axis

Homework Statement A thin rod has mass M and length L. What is the moment of inertia tensor about the center of mass if placed along the x axis. Homework Equations I would write the inertia tensor in component notation, but I don't know how to use Latex. The Attempt at a Solution...

Any ideas?
9. ### Energy in infinite square well

I don't think it's an algebraic error. I have worked the problem through, once using endpoints x=0 and x=L and again using x=-L/2 and x=L/2 and I don't get the same answer. In the case where I am going from 0 to L, I get that the energy is E=(n^2*h^2)/8mL^2, which is correct. In the case...
10. ### Energy in infinite square well

Homework Statement Find the energy of a particle of mass m in an infinite square well with one end at x=-L/2 and the other at x=L/2. Homework Equations Schrodinger Equation The Attempt at a Solution To save time, I won't type the solving of the differential equation which results...
11. ### Relative speed of two particles

Nevermind, I got it. Thanks SammyS.
12. ### Relative speed of two particles

Okay, so v dot u in the denominator will be zero, leaving just the 1. However, I'm still confused about u(perp) and u(para). Wouldn't u(perp) just be u and u(para) just be zero?
13. ### Relative speed of two particles

Homework Statement One particle is shot in the x direction at speed u and a second is shot in the y direction at speed u as well. Show that the relative speed of one to the other is: u(2-(u/c)^2)^1/2. Homework Equations velocity addition: u = (u' +/- v)/(1 +/- u'*v) Lorentz Trans...

Yes, you're right. I had drawn my line incorrectly. Instead of drawing it as .8c I drew it as 5/4 c. I've got it now. Thanks.

Each of the spaceships are moving towards each other. So the ship that launches from x=0 is moving towards x=4 and vice versa. I am giving the coordinates as (x,t).

Homework Statement Two rockets are sent off at t=0, one from x=0 and the other at x=4. The rocket leaving from x=0 is moving at .8c and the rocket leaving x=4 is moving at .2c. When the paths of the two rockets meet, they send a light signal to x=0. Read off the coordinates in the S frame...
17. ### Solving Central Force Motion: Sketch Equivalent Elliptic & Hyperbolic Orbits

Homework Statement Sketch the elliptical and hyperbolic orbits two objects make around each other if their masses are equal. Next to each, sketch the equivalent one-body orbit. Homework Equations The Attempt at a Solution For the elliptical orbit, I just drew two ellipses that...
18. ### Differentiating a constraint equation

Okay, thank you. That is what I was looking for. I just wasn't sure if I had to treat my r' as another variable or if I could consider it to be constant with the 2c. Thanks very much.
19. ### Differentiating a constraint equation

Homework Statement z = cr^2 Homework Equations The Attempt at a Solution I have a pretty simple question. What is the second derivative of the z equation. I know that z' = 2crr'. Am I correct to say that z'' = 2cr'^2 or is it something else? Hopefully my question...
20. ### Finding the force of constraint

So I still don't see what the point of finding this equation was. I was able to find the Lagrangian and go through and solve for the equation of motion all without having this equation.
21. ### Finding the force of constraint

You mean like 1/2Mv^2 = Mg(L - Lcos(theta)) V = sqrt[2g(L - Lcos(theta))]
22. ### Finding the force of constraint

Okay, so when swinging: T - Mgcos(theta) = Mv^2/L I still don't see how this equation helps at all.
23. ### Finding the force of constraint

Homework Statement A simple pendulum has a mass M attached at the end of a massless rod of length L. Find the force of constraint the rod exerts on the bob. Homework Equations The Attempt at a Solution It seems easy enough that the mass is constrained by the tension the rod...
24. ### Motion of a star in a galaxy

Homework Statement A star is moving in a circular orbit of radius r within a galaxy. What is it's orbital speed v(r) as a function of \rho(r) and radius. The galaxy is spherically symmetric with a mean density \rho(r) and radius R. Homework Equations F =...
25. ### Complex to polar form

What I'm saying is: x(t) = Ge^(i\phi) x(t) = G[cos(\omegat - \delta) + i*sin(\omegat - \delta) Then taking only the real part of this: x(t) = Gcos(\omegat - \delta). From here, I can compare to the given solution of x(t) = Dcos(\omegat - \delta) and say that G = D. Does this...
26. ### Complex to polar form

I am confused then because my question was from a test prep sheet from my professor. Should I perhaps only consider the real part of x(t)?
27. ### Complex to polar form

Why isn't x real?
28. ### Complex to polar form

Homework Statement Show that the solution x(t) = Ge^(iwt), where G is in general complex, can be written in the form x(t) = Dcos(wt - \delta). D(w) and \delta(w) are real functions of w. Homework Equations z = Ae^(i\phi) The Attempt at a Solution So I know I should start by...
29. ### Grade 11 Physics: Projectile Motion Calculations

It is basically a free fall problem.
30. ### Driven oscillator with damping

Homework Statement The oscillator is driven by a force F(t) = mAcos(wt). Plot the amplitude D of oscillations, in units of the maximum (resonant) amplitude D(max), as a function of w in units of w_0. (In other words, plot D/D(max) versus w/w_0.) Find Q. \beta=(1/6)w_0 Homework...
31. ### Finding initial projectile velocity with angle and a point in the path?

So first of all, the equation is delta Y = (Vo_y)*t + (1/2)(-9.8)t^2. It should not be a minus negative 4.9. You also left off the t^2. Also, your equation for delta x should be cos(36) not sin(36).
32. ### Finding initial projectile velocity with angle and a point in the path?

That is the correct equation for the x component of motion. However, the reason your getting stuck is because you need another equation so that you can eliminate the unknown variable time. This is where the y component of the motion will come in. Do this like you did to find the x component...
33. ### This is not my homework I am just curious

Think about it. The two cars are basically going through the same process. Each starts from rest and begins accelerating. The same equation will apply to both cars. The only difference is when each car starts. Think about how you can write the kinematic equation for the second car relative...
34. ### Solving for the Roots of Z^5 = -1

Okay, I see it now. Ya, I forgot n=4. I see what you mean about only having 5 answers because when n=5 it just cycles back around to (1/5)*pi. Thank you so much for your patience. I'm sure this was very frustrating for you.
35. ### Solving for the Roots of Z^5 = -1

Solving for theta and plugging in n=0,1,2,3... I get: theta = (1/5)*pi theta = (3/5)*pi theta = (5/5)*pi theta = (7/5)*pi
36. ### Solving for the Roots of Z^5 = -1

Actually it's neither of those. Since I don't know how to do this, I can't just look at an equation and know how to navigate my way to the final answer. Yes, I see your equation: (r^5)(e^(i*5*theta))=-1 This works when r=1 and theta=pi so this is one solution. This also works when r=-1...
37. ### Solving for the Roots of Z^5 = -1

Okay, thanks for the explanation diazona. However, let me show you my thought process. So I have already found that when theta=pi, 3pi, 5pi, 7pi, ... ; e^(i*theta) will equal -1. I also think that the only possible value for r is 1. So then you say I need to find what complex numbers when...
38. ### Solving for the Roots of Z^5 = -1

So: -1 + i*0 = cos(x) + i*sin(x) Therefore: cos(x) = -1 sin(x) = 0 To satisfy both these conditions, X can be any odd integer multiple of pi. cos(n*pi) = -1 for n= 1, 3, 5, 7, ... sin(n*pi) = 0 for n= 1, 3, 5, 7, ... I don't see how there can be a single specific answer. I...
39. ### Solving for the Roots of Z^5 = -1

I'm sorry. I don't see why it has to be a specific one. All of those work so how do I know which particular one is correct?
40. ### Solving for the Roots of Z^5 = -1

X could be any odd integer multiple of pi (i.e. pi, 3pi, 5pi, 7pi...). Is that what you are talking about?
41. ### Solving for the Roots of Z^5 = -1

Ya, I know. That was the hint I was given. However, I don't know exactly how to apply it in this situation. How do I get five roots from that equation?
42. ### Solving for the Roots of Z^5 = -1

Homework Statement Z^5 = -1 What are the five roots? Homework Equations The Attempt at a Solution I do not know how to start this problem. I am given a hint to put -1 into the form Ae^(i*delta), but I am unsure as to how I can do that. Any help would be much appreciated.
43. ### Complex Notation Homework: Solve for B & Phi in Terms of A, Omega, Delta

Actually, I think I might have something. Euler's formula says: e^(i*phi) = cos(phi) + i*sin(phi) The real part of this is: Re(e^(i*phi)) = cos(phi). Therefore, the real part of Be^(i*phi) is: Bcos(phi). So I have: X = Bcos(phi) and X = Acos(wt + delta) Am I able to...
44. ### Complex Notation Homework: Solve for B & Phi in Terms of A, Omega, Delta

Homework Statement If x= Acos(\omegat + \delta), then one can also write it as x = Re(Be^{i\Phi}). Find B and \Phi in terms of A, \omega, and \delta if B is real. Homework Equations The Attempt at a Solution Not sure where to start on this one. I know you guys can't give...
45. ### Testing First exam results are back, and I need to up my game

I usually make sure that I can work through every example that is in the textbook on my own. A lot of times, a professor will use an example from straight out of the book or use a slight variation of the example. Other than that, I use the first test of the semester to gauge how he/she asks...
46. ### One pulley attached between two blocks, both sliding on wood.

Find all the forces acting on block 1 and set that equal to m1a. Then find all the forces acting on block two and set that equal to m2a. Then by solving for T, you can get the equation down to one variable and solve for m1.
47. ### One pulley attached between two blocks, both sliding on wood.

You need to set up an equation of motion for block one and block two separately. You can also use the fact that the tension in the rope attached to block 1 is equal to the tension in the rope attached to block 2. Then you can solve for m1.
48. ### Calculating Minimum Required Velocity

So you want the projectile to be able to stop on top of the building, not just clear it?
49. ### Circular motion and radial acceleration

This does not even require any work. Just use dimensional analysis. First figure out what the units of angular acceleration are. Since you know what the units of time are, figure out which choice yields units of seconds.
50. ### Physics-magnitude/ displacement?

Make sure you make the correct conversions. I don't know what units your answer needs to be in, but it may be km/s, km/hr, or m/s.