At the beginning of World War II, there was a need for an effective lightweight anti-tank weapon that a single soldier could carry. The United States military introduced the most famous one--the bazooka, named after a musical horn used by American comedian Bob Burns. The bazooka was developed in 1941 and first used by American troops in late 1942. The principle behind the bazooka goes back to English physicist Sir Isaac Newton (1642-1727) and his three laws of motion, in which he stated that for every force there is an equal and opposite force. The bazooka had a warhead with a rocket motor that produced pressurized gas which escaped through a nozzle; this force heading out of the nozzle produced an equal and opposite force driving the warhead forward. The bazooka was fairly simple in design. There was a 3.5-pound (1.6 kg), 21-inch (53 cm) rocket made up of a fused warhead...