1. A baseball fan sitting the “cheap seats” is 255m from home plate. How much time elapses among the instant the fan sees a batter hit the ball and the moment he hears the sound?
2. A camera is equipped by a lens with a focal length of 30cm.when an object 2 m (200cm) away is being photographed; how far from the field must the lens be placed? What is the magnification?