Amerry-go-round, with mass m and moment of inertia i, spins with angular speed ω on the earth’s equator. the merry-go-round’s surface is parallel to the earth’s surface with the y-axis oriented north and the x-axis oriented east. viewed from above the merrygo-round spins counter-clockwise, and viewed from above the north pole the earth rotates counter-clockwise. if tday is one day, and re is the earth’s radius, what is the total angular momentum of the merry-go-round about the center of the earth?

Conventional hot-water heaters consist of a tank of water maintained at a fixed temperature. the hot water is to be used when needed. the drawback is that energy is wasted because the tank loses heat when it is not in use, and you can run out of hot water if you use too much. some utility companies are encouraging the use of on-demand water heaters (also known as flash heaters), which consist of heating units to heat the water as you use it. no water tank is involved, so no heat is wasted. a typical household shower flow rate is 2.50 gal/min (9.46 l/min ) with the tap water being heated from 51.0 ˚f (10.6 ˚c) to 120 ˚f (48.9 ˚c) by the on-demand heater.what rate of heat input (either electrical of from gas) is required to operate such a unit, assuming that all the heat goes into the water?