Recent content by jesuslovesu

Homework Statement I am in the process of doing a physics problem with a differential equation that has the form: y = Acos(kx) + Bsin(kx) According to my notes, this can also be written as y =Aejkx + Be-jkx, unfortunately I just don't see how to write the original equation like that...

Homework Statement A hydrogen atom has its electron in the n = 2 state. The electron makes a transition to the ground state. The linear momentum of the emitted photon is E/c. If we assume conservation of linear momentum, what is the recoil velocity of the atom? Homework Equations v_n =...

Homework Statement Supopse that a 100 W source radiates light of wavelength 600 nm in all directions and that the eye can detect this light if only 20 photons per second enter a dark adapted eye having a 7 mm diameter pupil. How far from the source can the light be detected under these...

Homework Statement For a cubic crystal lattice: The intercepts of a plane are -1, 1, and 2 along the x, y, and z axes, respectively. The Miller index is (!2 2 1). Find the direction vector normal to the plane.Homework Equations The Attempt at a Solution In my book it states that a cubic...

Homework Statement A gun is fired straight up. Assume a quadratic drag force. Show (upward motion) v^2 = Ae^{-2kx} - \frac{g}{k} (downward motion) v^2 = g/k - Be^{2kx} Homework Equations The Attempt at a Solution I can easily solve the integrals unfortunately I am having difficulty setting...

[solved] Step Force Never mind, i think i figured it out Homework Statement Suppose a body of mass m is subject to a constant force F_1 that acts for a length time t_1 and then the force suddenly changes to a constant F_2 Show v(t) = v_0 + \frac{F_1 t_1}{m} + \frac{F_2(t-t_1 )}{m} x(t) =...

Ok got it thanks.

Homework Statement Use the scalar projection to show that a distance from a point P(x1, y1) to the line ax + by + c = 0 is \frac{ax1 + by1 + c}{\sqrt{a^2 + b^2}}Homework Equations scalar projection = \frac{a . b}{|a|} The Attempt at a Solution The first thing that I did was to say that b =...

Internships/Coops Hey guys, I will most likely have the opportunity to get an internship or co-op at my father's place of work. Unfortunately, what the engineers do there has nothing to do with what I would actually like to do. My question is would this affect me negatively if I were to get an...

Homework Statement A = (1,1,-2) C = (0,1,-5) (in cartesian coordinates) Let A and C be drawn from a common origin and let C rotate about A with an angular velocity of 2 rad/s. Find the velocity of the head of C. Homework Equations v = w x r The Attempt at a Solution w = 2...

[SOLVED] Laplace Transform Homework Statement Suppose F(s) = \displaystyle\mathcal{L}(f(t)) Show that \displaystyle\mathcal{L}(f(ct)) = 1/c F(s/c) Homework Equations The Attempt at a Solution \displaystyle\mathcal{L}(f(t)) = \int_0^{inf} e^{-st} f(t) dt \displaystyle\mathcal{L}(f(ct)) =...

got it now thanks, those steps are really handy

Unfortunately I haven't studied complex analysis. I made an error in my original post (and I can't edit it for some reason) It's now worse than before s^2 + s - 2 = (s+2)(s-1) -\frac{e^{-2s}}{3(s+2)} + \frac{e^{-2s}}{3(s-1)} I see the time shift equation on wikipedia, but since the 's' is in...

[SOLVED] Laplace transform Homework Statement Find the inverse laplace transform of \frac{e^{-2s} }{s^2 + s - 2} Homework Equations The Attempt at a Solution I'm able to do about half of the problem using partial fractions, I've found...

[SOLVED] Trig Question Homework Statement Let's say I have tan(2\theta) = cot(\phi) I'm not quite sure how to simplify it (I want to solve for theta) I could say tan(2\theta) = 1 / tan(\phi) 2\theta = atan( 1 / tan(\phi) ) but then I'm not sure what to do after that. Do I take the atan of 1...