Directions: 1. Put the tack on a table, and hold the point of the nail over it.

2. Then slowly move your magnet toward the other end of the nail.
Answer the following questions.

a. Does the magnet have to be touching the nail to lift the tack or paper clip?

b. How close does it have to be? Experiment with different sized magnets.

c. Does the size of the magnetic field change with the size of the magnet?

The key to stability is feedback between the reservoir and the fluxes into and/or out of the reservoir. assume that the rate of outflow from a reservoir depends on the size of the reservoir according to the following relationship: outflow rate= k x (size of reservoir), where k is a constant. a reservoir of water has a volume of 5000 liters, and the rate of outflow at steady state is 25 liters per minute. what is k? (give both the numerical value and its units.) what is the residence time? what is the relationship between k and the residence time?

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

What causes the formation of ocean currents?