. A box of weight 220 N is being pulled to the right by a pulling force F of magnitude 30 N. The coefficient of static friction between the box and the floor is 0.15. To make an accurate free-body diagram of the box, the letter W in the diagram below should be replaced with the label .

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