To clearly read a book 42.5 cm away, a farsighted student needs the image to be 61.5 cm from her eyes. What must the focal length of the lenses in her eyeglasses be?

You are traveling in a car going at a constant speed of 100km/h down a long, straight highway. you pass another car going in the same direction which is traveling at a constant speed of 80km/h. as measured from your car's reference frame this other car is traveling at −20km/h. what is the acceleration of your car as measured from the other car's reference frame? what is the acceleration of the other car as measured from your car's reference frame?