Ateacher sets up a stand carrying a convex lens of focal length 15 cm at 20.5 cm mark on the optical bench. she asks the students to suggest the position of the screen on the optical bench so that a distinct image of a distant tree is obtained on it. what should be the correct position of the screen as suggested by the students and why?

You are driving to the grocery store at 20 m/s. you are 110m from an intersection when the traffic light turns red. assume that your reaction time is 0.50s and that your car brakes with constant acceleration. how far are you from the intersection when you begin to apply the brakes? what acceleration will bring you to rest right at the intersection? how long does it take you to stop after the light changes? the known values: vi=20m/s xi=110m t=.50s vf=0m/s xf=0m a=?