Find the minimum electric current that when it passes through a coil of a motor, it produces a torque of 20 N. m. If you know that the number of turns of the coil is 200 turns, its cross-
sectional area is 300 cm- and the magnetic flux density is 0.4 tesla.

Which of these is not a possible type of energy transformation? a. electrical energy into light energy b. sound energy into nuclear energy c. potential energy into kinetic energy d. kinetic energy into mechanical energy

Air is to be preheated by hot exhaust gases in a cross-flow heat exchanger before it enters the furnace. air enters the heat exchanger at 95 kpa and 20°c at a rate of 0.6 m^3/s. the combustion gases (cp = 1.10 kj/kg°c) enter at 160°c at a rate of 0.95 kg/s and leave at 95°c. determine the rate of heat transfer to the air and its outlet temperature.

Estimate the schwarzschild radius (in kilometers) for a mini-black hole formed when a superadvanced civilization decides to punish you (unfairly) by squeezing you until you become so small that you disappear inside your own event horizon. (assume that the your weight is 50 kg)