Bill kicks a rock off the top of his apartment building. it strikes a window across the street 13 m away. the acceleration of gravity is 9.8 m/s 2 . if the window is 25 m below the position where bill contacted the rock, how long was it in the air? answer in units of s.

Athin nonconducting rod with a uniform distribution of positive charge q is bent into a circle of radius r. the central perpendicular axis through the ring is a z-axis, with the origin at the center of the ring. a) what is the magnitude of the electric field due to the rod at z = 0? n/c (b) what is the magnitude of the electric field due to the rod at z = infinity? n/c (c) in terms of r, at what positive value of z is that magnitude maximum? r (d) if r = 4.00 cm and q = 9.00 µc, what is the maximum magnitude? n/c