You are helping to design a new fire escape for your third-floor apartment. You step out the window onto a crossbar that is attached to a rope, which in turn is wound around a massive solid cylindrical flywheel that can turn on its axis.
As you fall at increasing speed, the rope causes the flywheel to turn at increasing angular velocity. Your task is to
choose a flywheel that will enable you to move at a safe 2.0 m/s when you reach 10 m below your starting position.
Your mass is 80 kg. Determine the rotational inertia and mass of the uniform 0.80 m radius flywheel you need to
buy.

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?