The projection lens in a certain projector is a single thin lens. an object 23.7 mm high is to be projected so that its image fills a screen 1.71 m high. the lens-to-screen distance is 3.04 m. determine the focal length of the lens.

Suppose a force of 60 n is required to stretch and hold a spring 0.1 m from its equilibrium position. a. assuming the spring obeys hooke's law, find the spring constant k. b. how much work is required to compress the spring 0.5 m from its equilibrium position? c. how much work is required to stretch the spring 0.6 m from its equilibrium position? d. how much additional work is required to stretch the spring 0.1 m if it has already been stretched 0.1 m from its equilibrium? a. kequals 600