Electric current first flows out the top of the battery, through the wire and bulb and then returns via the bottom wire. So it always flows in a loop and two wires are needed to connect the voltage source to the load. In this example of a simple circuit, an AA cell forces current ...
The exhaust gases rush past a set of turbine blades, spinning them like a windmill. Since the turbine gains energy, the gases must lose the same amount of energy—and they do so by cooling down slightly and losing pressure. The turbine blades are connected to a long axle (represented by ...
If ramjets are so fiddly, then why bother? Well, at the pressures and temperatures generated at Mach 2.5+, most jet engines become hugely impractical -- and utterly pointless. Even if you could make one work, doing so would combine the hazards of running a windmill in a hurricane with th...