An aluminum rod with a mass of 0.220 kg slides on parallel horizontal steel rails, 0.440 m apart, and carries a current of 15.0 A. The coefficient of friction between the rod and rails is 0.470. What vertical, uniform magnetic field is needed to keep the rod moving at a constant speed

Amplitude is a measure of a waves a; speed b; distance c; energy d; frequency

People with normal vision cannot focus their eyes underwater if they aren't wearing a face mask or goggles and there is water in contact with their eyes. in a simplified model of the human eye, the aqueous and vitreous humors and the lens all have a refractive index of 1.40, and all the refraction occurs at the cornea, whose vertex is 2.60 cm from the retina. 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 2.05cm in front of the eye.)

How much work would it take to move a coulomb charge across a 4 volt potential difference?