A lift travelling up to the top floor of the Empire State building with a mass of 4200kg and kinetic energy of 4116J. What's the velocity?

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

Aforklift raises a box above the floor and does 2,000 j of work. if the forklift motor consumes 3,000 j of electrical energy from the battery to raise the box, what is the efficiency of the lift?

Jaylen is a championship runner of the school's track team. during one of his trials, his speed was measured at 15.1 m/s. find jaylen's kinetic energy during that trial if his mass is 54.6 kg.