You are driving slowly on the highway at 50 mph when a police car with its lights flashing passes you going 100 mph. relative to you, the police officer is moving 50 mph. far in the future, when humans have mastered space travel, an astronaut is moving in a spaceship at half the speed of light, v = c/2, relative to earth, when a light beam sent from earth moving parallel to the spaceship passes it moving at v = c. the astronaut measures the light beam to be moving ata. v=2c b. v=c/2 c. v=c d. v=3c/2

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