We take shortcuts all the time with our physical models. We rarely consider that the wire has resistance, for example, or that batteries have a source impedance. It’s fine until the point it’s not. Take the case of the Navy’s Grumman F11F Tiger aircraft. The supersonic aircraft was impressive, although it suffered from some fatal flaws. But it also has the distinction of being the first plane to ever shoot itself down.
So here’s the simple math. An airplane traveling Mach 1 is moving around 1,200 km/h — the exact number depends on a few things like your altitude and the humidity. Let’s say about 333 m/s. Bullets from a 20 mm gun, on the other hand, travel at more than 1000 m/second. So when the bullet leaves the plane it will take the plane over three seconds to reach it, and by then it’s moved further and further away, right?
Continue reading “The Importance of Physical Models: How Not to Shoot Yourself in the Foot or Elsewhere”