9) During 5th period Dylan was a beast. She resisted the forces applied by 13 other students in her class all at once. Her 13 classmates tried to knock Dylan over, each applying a force of 17 N, and she still didn't budge. How much force was Dylan
pushing back with, and how many people would it take to push Dylan if she can withstand a force of 300 N?

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