A heart defibrillator is used to enable the heart to start beating if it has stopped. This is done by passing a large current of 12 A through the whole body at 25 V for a very short period of time, usually about 3 ms. What power does the defibrillator deliver to the body, and how much total energy is transferred?

Suppose that two tanks, 1 and 2, each with a large opening at the top, contain different liquids. a small hole is made in the side of each tank at the same depth 1.57 m below the liquid surface, but the hole in tank 2 has 2.49 times the cross-sectional area of the hole in tank 1. (a) what is the ratio ρ1/ρ2 of the densities of the liquids if the mass flow rate is the same for the two holes? (b) what is the ratio rv1/rv2 of the volume flow rates from the two tanks? (c) at one instant, the liquid in tank 1 is 14.9 cm above the hole. if the tanks are to have equal volume flow rates, what height above the hole must the liquid in tank 2 be just then?

The energy equivalent of the rest mass of an electron is

Does heating a metal wire increase or decrease its electrical resistance? why?