How can I make a square fit in a triangle hole

With the simplified model of the eye, what corrective lens (specified by focal length as measured in air) would be needed to enable a person underwater to focus an infinitely distant object? (be careful-the focal length of a lens underwater is not the same as in air! assume that the corrective lens has a refractive index of 1.62 and that the lens is used in eyeglasses, not goggles, so there is water on both sides of the lens. assume that the eyeglasses are 1.90

Awater slide of length l has a vertical drop of h. abby's mass is m. an average friction force of magnitude f opposes her motion. she starts down the slide at initial speed vi. use work-energy ideas to develop an expression for her speed at the bottom of the slide. then evaluate your result using unit analysis and limiting case analysis. express your answer in terms of the variables h, m, l, vi, f and appropriate constants. vf v f

Aman is trying to drag a small tree that he cut down. if the static coefficient of friction of the tree on the ground is 0.5 and the tree weighs 670 n, what is the minimum amount of horizontal force that the man will need to apply so that the tree will start moving? o a. 465 n o b. 230 n o c. 670 n o d. 335 n