{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

finalsoln_07

# finalsoln_07 - Physics 9B-C Final Exam Solutions Cole UC...

This preview shows pages 1–2. Sign up to view the full content.

A A net ƒ = π /2 Phy 9B-C, Final Solutions Page 1 of 3 12/15/05 A A net = Physics 9B-C Final Exam Solutions Cole, UC Davis 20 points per problem/200 points total [1] (a) False (b) blue (c) right (d) minimum (e) 1/ r (f) dimmer (g) increase (h) least (i) black (j) Î S ≥  0. [2] a) (8 pts) Plug the solution into the wave equation. First calculate the second derivatives: & 2 y t 2 = ω 2 A sin kx ω t ( ) Also, 2 y x 2 = k 2 A sin kx ω t ( ) . Plug into the wave equation: - 2 A sin( kx - t) + u 2 k 2 A sin( kx - t ) + å A sin( kx - t ) = 0 Divide by the A sin and solve for : ∑  = u 2 k 2 + α which is the dispersion relation. b) (4 pts) v p = ω k = u 2 + α k 2 c) (4 pts) v g = d ω dk = d dk u 2 k 2 + α = 1 2 u 2 2 k ( ) u 2 k 2 + α õ v g = u 2 k u 2 k 2 + α d) (4 pts) Write the phase velocity in terms of ¬ using k = (2 π )/¬: v p = u 2 + α 4 π 2 λ 2 Thus, longer wavelengths will have a greater phase speed. [3] A) (5 pts) Match the boundary conditions. The free ends must have antinodes, and there must be a node at each support. The fundamental obeying the boundary conditions is shown to the right where, ¬ = L õ k = 2 π λ = 2 π L = 2 π 1.2 m õ k = 5.23/m. b) (5 pts) ∑  = vk = (3000 m/s)(5.23/m) = 1.57 ª 10 4 /s c) (10 pts) For a standing wavefunction the possibilities are sin-sin, sin-cos, cos-sin, cos-cos.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern