A door 94 cm by 186 cm of mass 18 kg hangs on two H I N G E S. One is attached to the bottom of one side of the door and the other to the top of the same side. What is the magnitude of the horizontal force on the door by the bottom H I N G E? What's the magnitude of the horizontal force on the door by the top H I N G E?

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