# Search results

1. ### Lens maker's equation used correctly?

Homework Statement An object is placed 60 cm from a thick double convex lens, with faces of radii of curvature 20 cm and 30 cm, with thickness of 2 cm, and index of refraction is 1.5. Find the position of the image...
2. ### Difference between two wave functions?

Hi, I'm looking through my teacher's notes and he says that a wave function for a sinusoidal wave can be written: y = A sin (ω t – k x) or y = A sin (k x - ω t) The textbook gives it in the second form. I think that using one over the other gives the same answer but in the opposite sign. I...
3. ### Finding electric field via a given potential

Homework Statement The plastic rod of the length L=1 m has a non-uniform charge density λ=cx where positive constant c =2x10^-6 [some unit]. What unit c has to have? Find the electric potential at the point on the x axis 1 m to the left from the left end of the rod. Find the electric field at...
4. ### Finding electric field via potential

Homework Statement The plastic rod of the length L=1 m has a non-uniform charge density λ=cx where positive constant c =2x10^-6 [some unit]. What unit c has to have? Find the electric potential at the point on the x axis 1 m to the left from the left end of the rod. Find the electric...
5. ### Can you clarify this step (charge density and integrals).

Hi, if you have the book: Physics for Scientists and Engineers 8E, Serway Jewett On page 675 (Chapter 23), Example 23.8 there is a step taken during the integration I don't understand: How do you go from "2r dr" in the numerator to d(r^2)? If there is info or link to the property of...
6. ### For those who have this textbook.

Homework Statement In Physics for Scientists and Engineers Volume 1 Eighth Edition (Serway, Jewett) Number 55. in Chapter 5, I checked the answer key and would like to know why they don't consider the forces of friction in a), b), c), d), and e)? This confuses me. Thank you. Homework...
7. ### How to define change of angular momentum in non-isolated system?

Homework Statement http://tycho.physics.wisc.edu/courses/phys201/fall06/Discussion/Disc14Solution.pdf [Broken] problem 38, part b) Homework Equations I final w final = I initial w initial The Attempt at a Solution I understand that the snowball is introducing a net torque and I know that...