Principles of Physics 2 Problem (Calculus based) Help A thin cylindrical shell of radius R and length L, like a soda straw, is uniformly charged with surface charge density η. What is the electric field strength at the center of one end of the cylinder? The answer is supposed to be , where E(sub 0) is epsilon 0 and the "n" is the surface charge density (η). Can someone explain how to get the answer? Kind of confused on what to do.

Consider a uniformly charged ring in the xy plane, centered at the origin. the ring has radius a and positive charge qdistributed evenly along its circumference. a)what is the direction of the electric field at any point on the z axis? . b)what is the magnitude of the electric field along the positive z axis? use k in your answer, where k=14πϵ0. d)the ball will oscillate along the z axis between z=d and z=−d in simple harmonic motion. what will be the angular frequency ω of these oscillations? use the approximation d≪a to simplify your calculation; that is, assume that d2+a2≈a2. express your answer in terms of given charges, dimensions, and constants