Try to find out about 'Fresnel' lens on an overhead projector, or stage light. What shape is its surface? Make a drawing to show how it can focus light? What could a concave Fresnel be used for?

Amoving company collects data about couches they move and displays the data in a table. the force along the ramp, the angle of the ramp, and the height the couch is raised to are shown. which statements correctly compare the work done to move the couches? check all that apply. the same amount of work is done for couches 1 and 3. the same amount of work is done for couches 2 and 3. the work for couch 1 is greater than the work for couch 2. the work for couch 2 is less than the work for couch 3. the work for couch 3 is greater than the work for couch 1. the work for couch 2 is greater than the work for couch 1.